The Effectiveness of Aromatherapy in Reducing Pain: A Systematic Review and Meta-Analysis

Abstract

Background. Aromatherapy refers to the medicinal or therapeutic use of essential oils absorbed through the skin or olfactory system. Recent literature has examined the effectiveness of aromatherapy in treating pain. Methods. 12 studies examining the use of aromatherapy for pain management were identified through an electronic database search. A meta-analysis was performed to determine the effects of aromatherapy on pain. Results. There is a significant positive effect of aromatherapy (compared to placebo or treatments as usual controls) in reducing pain reported on a visual analog scale (SMD = −1.18, 95% CI: −1.33, −1.03; p<0.0001 ). Secondary analyses found that aromatherapy is more consistent for treating nociceptive (SMD = −1.57, 95% CI: −1.76, −1.39, p<0.0001 ) and acute pain (SMD = −1.58, 95% CI: −1.75, −1.40, p<0.0001 ) than inflammatory (SMD = −0.53, 95% CI: −0.77, −0.29, p<0.0001 ) and chronic pain (SMD = −0.22, 95% CI: −0.49, 0.05, p=0.001 ), respectively. Based on the available research, aromatherapy is most effective in treating postoperative pain (SMD = −1.79, 95% CI: −2.08, −1.51, p<0.0001 ) and obstetrical and gynecological pain (SMD = −1.14, 95% CI: −2.10, −0.19, p<0.0001 ). Conclusion. The findings of this study indicate that aromatherapy can successfully treat pain when combined with conventional treatments.

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Research Article
The Effectiveness of Aromatherapy in Reducing Pain:
A Systematic Review and Meta-Analysis
Shaheen E. Lakhan,1,2 Heather Sheafer,1and Deborah Tepper3
1Global Neuroscience Initiative Foundation, Los Angeles, CA, USA
2California University of Science and Medicine, School of Medicine, Colton, CA, USA
3Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
Correspondence should be addressed to Shaheen E. Lakhan; slakhan@gnif.org
Received  September ; Accepted  November 
Academic Editor: Giustino Varrassi
Copyright ©  Shaheen E. Lakhan et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Background. Aromatherapy refers to the medicinal or therapeutic use of essential oils absorbed through the skin or olfactory
system. Recent literature has examined the eectiveness of aromatherapy in treating pain. Methods.  studies examining the use
of aromatherapy for pain management were identied through an electronic database search. A meta-analysis was performed
to determine the eects of aromatherapy on pain. Results. ere is a signicant positive eect of aromatherapy (compared to
placebo or treatments as usual controls) in reducing pain reported on a visual analog scale (SMD = −., % CI: −., −.;
𝑝 < 0.0001). Secondary analyses found that aromatherapy is more consistent for treating nociceptive (SMD = −., % CI: −.,
−., 𝑝 < 0.0001)andacutepain(SMD=−., % CI: −., −., 𝑝 < 0.0001) than inammatory (SMD = −., % CI: −.,
−., 𝑝 < 0.0001) and chronic pain (SMD = −., % CI: −., ., 𝑝 = 0.001), respectively. Based on the available research,
aromatherapy is most eective in treating postoperative pain (SMD = −., % CI: −., −., 𝑝 < 0.0001)andobstetrical
and gynecological pain (SMD = −., % CI: −., −., 𝑝 < 0.0001). Conclusion. e ndings of this study indicate that
aromatherapy can successfully treat pain when combined with conventional treatments.
1. Introduction
Aromatherapy refers to the medicinal or therapeutic use of
essential oils absorbed through the skin or olfactory system
[, ]. Essential oils, which are derived from plants, are used to
treat illness as well as to enhance physical and psychological
well-being. Although the use of distilled plant materials dates
back to medieval Persia, the term “aromatherapy” was rst
used by Rene Maurice Gattefosse in the early th century.
In his  book, Aromatherapie,Gattefosseclaimedthat
herbalmedicinecouldbeusedtotreatvirtuallyanyailment
throughout the human organ system. Today, aromatherapy is
popularintheUnitedStatesandaroundtheworld[].
Although many claims have been made relating to the
benets of aromatherapy, most research has focused on its
use to manage depression, anxiety, muscle tension, sleep
disturbance, nausea, and pain []. Some studies suggest that
olfactory stimulation related to aromatherapy can result in
immediate reduction in pain, as well as changing phys-
iological parameters such as pulse, blood pressure, skin
temperature, and brain activity []. Although the benets
remain controversial, many patients and healthcare providers
are attracted to aromatherapy because of its low cost and
minimal side eects. Essential oils currently available for
medicinal use are generally recognized as safe by the United
States Food and Drug Administration (FDA). In some cases,
essential oils can cause minor skin irritation at the site of
use. If ingested in large amounts, essential oils can cause
phototoxic reactions which can, in rare instances, be lethal
[].
Aromatherapy is most commonly applied topically, or
through inhalation. When applied topically, the oil is usually
added to carrier oil and used for massage. Essential oils can
be inhaled through a humidier or by soaking gauze and
placing it near the patient []. Olfactory and tactile sensory
stimulation produced by these oils can enhance ordinary
Hindawi Publishing Corporation
Pain Research and Treatment
Volume 2016, Article ID 8158693, 13 pages
http://dx.doi.org/10.1155/2016/8158693

Pain Research and Treatment
human activities such as eating, social interaction, and sexual
contact []. While more than  plant derivatives have been
identied for therapeutic use, lavender, eucalyptus, rosemary,
chamomile, and peppermint are the most frequently utilized
extracts [].
Even though aromatherapy is commonly used and has
been practiced for centuries, few high quality empirical re-
views have examined its eectiveness in reducing pain.
A database search revealed that common end points for
aromatherapy research oen focus on the reduction of psy-
chological symptoms such as depression and anxiety or
seek to measure the increase of patient satisfaction. Many
studies examining the use of aromatherapy in pain reduction
focus on therapeutic massage rendering the isolated impact
of essential oils without massage unclear. Obstetrical and
gynecological pain has garnered the greatest attention when
examining the ecacy of aromatherapy. To date, no meta-
analysis has expressly examined the use of aromatherapy
for pain reduction and management. e aim of this meta-
analysis was to quantify the eectiveness of aromatherapy for
pain management.
2. Methods
2.1. Literature Search Strategy. To retrieve available evidence
relatedtotheuseofaromatherapyforpainmanagement,the
author conducted an electronic database search of PubMed,
Science Direct, and the Cochrane Library using PRISMA
and Cochrane guidelines. Each database was searched using
the following MeSH terms: aromatherapy, essential oils AND
pain, pain management. Articles identied in this manner
were retrieved and their reference lists searched for additional
relevant articles.
2.2. Selection of Studies. An initial database search yielded
 articles related to aromatherapy and pain management.
For the qualitative analysis (systematic review), eligible stud-
ieswerepublishedinEnglishandfocusedontheuseof
aromatherapy to manage pain. For the quantitative analysis
(meta-analysis), however, several exclusions were used to
prevent the analysis of irrelevant or poorly designed studies.
Eligible studies were published in English and measured
pain on a visual analog scale (VAS). Studies with no pain
scale or other measures of pain were excluded. For example,
studies that measured the eectiveness of aromatherapy
by comparing it to the request or need for an additional
pain intervention were excluded. Vague measures such as
pleasantness and patient satisfaction were also excluded.
Similarly, studies that measured pain and other conditions,
such as nausea, in a single scale were excluded. Additionally,
studies using measures unrelated to pain such as redness,
inammation, and cardiovascular or respiratory conditions
were excluded. Next, only experimental study designs were
included. Case studies and studies with no control were
excluded. Finally, all eligible studies included at least one
measure of pain. Studies that only reported other conditions,
such as mood or agitation, were excluded.
2.3. Data Extraction. Data was extracted independently for
each study included. Although mood measures were included
when available, data for nonpain physical measures such as
redness, inammation, and heart rate were not extracted,
even when pain was measured. Additionally, data on dif-
ferences in analgesic use was not extracted. If measures
were reported at intervals during treatment, only total mean
change or nal mean change was used for analysis.
2.4. Data Analysis. e primary end point for this study
was the use of aromatherapy for pain management. For each
study, the standardized mean dierence (SMD) of VAS pain
between the treatment and control group was calculated.
Eect sizes were calculated for all included studies using Stata
version . Cohen’s recommended eect size was considered,
with a size of . indicating a small eect, . indicating
a moderate eect, and . indicating a large eect. A %
condence interval was used to calculate pooled eect sizes
reported as standardized mean dierence. For studies overall,
andeachsubgroup,heterogeneitywasconsideredhighat𝐼2≥
75%, moderate at 𝐼2=50%, and low at 𝐼2≤25%.
Secondary endpoints included inammatory pain versus
nociceptive pain, chronic versus acute pain, postoperative
pain versus nonpostoperative pain, and gynecological pain
versus nongynecological pain.
Risk for publication bias was assessed using funnel plots.
3. Results
Of  records screened,  were included in the qualitative
synthesis (systematic review) and  in the quantitative
synthesis (meta-analysis) (see Figure  for owchart). ose
not included in the review were rejected because of poor
study design, non-VAS pain measures, reporting conditions
not related to pain, or were reviews or meta-analyses (though
some of these papers are referenced to provide background
information).
3.1. Systematic Review
3.1.1. Chronic Pain in Older Adults. As many as % of
older adults living in nursing homes suer from chronic
pain. Unlike pain among other populations, this chronic
pain is persistent, complex, and oen not associated with
diagnosableconditions.Frequentlythepainisassociatedwith
stress and poor coping abilities. Chronic pain oen leads to
other conditions, such as poor sleep, anxiety, depression, and
overall reduction in quality of life. A prospective, randomized
three-group control trial tested the ecacy of aromatherapy
hand massage among nursing home patients suering from
chronic pain. Ailments varied and included physical and psy-
chological complaints such as hypertension, depression, heart
disease, arthritis, dementia, healed injuries, and psychiatric
illnesses. e majority of patients took daily pain medication
and more than half were being treated with antidepressant
medication [].
Participants in the intervention group received hand
massage with lavender essential oil while the control group
receivedhandmassagealone.Athirdgrouphadregularnurse

Pain Research and Treatment 
IdenticationScreeningEligibilityIncluded
Records identied through database searching
(n = 353)
Records aer duplicates removed
(n = 293)
Records screened
(n = 293)
Studies included in
qualitative analysis
(n=42)
Studies included in
quantitative synthesis
(meta-analysis)
(n=12)
Records excluded
(n = 251)
Published in language other than English
(n=54)
Not relevant (n = 197)
Full-text articles excluded,
(n=30)
Vague pain scale or measure other than pain
(n=6)
Mean dierence not provided (n=2)
Postintervention sample size not provided
(n=3)
Multiple factors or nonpain factors included in
single pain scale (n=4)
Systematic review (n=4)
Study data not fully reported (n=2)
No control group, or control group is irrelevant
(n=5)
Measures an intervention other than
aromatherapy (n=3)
Case study (n=1)
F : Flowchart of studies that met inclusion/exclusion criteria for qualitative and quantitative analyses.
visits, but no hand massage. Although both massage groups
reported a marked dierence in pain and overall well-being,
there was no signicant dierence between the two massage
groups. One reason for this nding could be that older adults
naturally experience a decreased sense of smell as they age.
Sense of smell was not measured at any time during the
study, so it is possible that the two massage groups did not
experience any dierence in treatment [].
3.1.2. Chronic Back Pain. Approximately –% of older
people in the U.S. experience back pain at least once during
their lives, with % experiencing a period of lower back pain
each year []. Unspecied lower back pain is among the top
mostcommonhealthcareprovidervisits.Treatmentcanbe
dicult to get because less than % of patients experiencing
lowbackpainarediagnosedwithaknowncause.erefore,
treatment options tend to focus on symptoms rather than
cause []. Chronic lower back pain is associated with poor
quality of life, reduced physical activities, and oen leads
to loss of work and productivity. Massage is a common
treatment for lower back pain, but the eects of aromatherapy
in conjunction with massage are unknown [].
In a randomized controlled trial to investigate the eect
of combining acupressure with lavender essential oil for
pain relief of subacute and chronic lower back pain, par-
ticipants who received a -week course of eight sessions
of treatment showed a signicant reduction in subjective
pain intensity and an improvement in objective measures

Pain Research and Treatment
of physical functional performance, including lateral spine
exionandwalkingtime.eresultsofthestudysupportthat
acupressure type massage with lavender oil may help improve
subacute lower back pain. However there was no group
that received acupressure without lavender oil, so it is not
possible to say denitively whether the improvement came
from the aromatherapy or the massage intervention alone.
e researchers recommend that the combined treatment be
used along with mainstream medical treatment, as an add-on
therapy in reducing lower back pain in the short term [].
A separate randomized control trial compared partici-
pants who received Swedish massage using ginger oil with a
control group who received traditional ai massage through
clothes with no oil. In this trial, participants were assessed
 months aer treatment to determine the long-term eects
of aromatherapy. e researchers found that both massage
groups experienced a signicant improvement in pain and
mobility. However, the patients whose massage contained
ginger oil experienced better outcomes across categories for
longer periods of time [].
3.1.3. Chronic Neck Pain. Like chronic back pain, chronic
neck pain can be severely debilitating. An experimental study
compared the results of patients who received acupoint elec-
trode stimulation combined with aromatherapy acupressure
in addition to conventional treatment versus conventional
treatment alone for neck pain. Aer eight lavender acu-
pressure and acupoint stimulation sessions, the increased
intervention group reported an improved range of motion,
reduced pain, reduced stiness, and reduced stress a month
aer treatment compared to those receiving usual treatment.
ese results indicate that aromatherapy is a viable option
for a complementary treatment in addition to conventional
treatment [].
3.1.4. Chronic Knee Pain. Knee pain is another common form
of pain experienced by adults over . Chronic knee pain
oen leads to functional impairment, reducing quality of
life. Like other treatments for chronic pain, conventional
treatments for knee pain focus on symptoms rather than
underlying cause. Many older adults turn to complementary
treatment for relief. In a double-blind, placebo-controlled
experimental study, massage with ginger oil was compared to
a massage only and a treatment as usual group. At one-week
follow-up, knee pain and stiness were similar among the
three groups. At the four-week follow-up, the aromatherapy
intervention group reported a reduction in knee pain rating.
is intervention group also demonstrated an improvement
in physical function compared to the control groups. Inter-
estingly, there was no signicant change in report of overall
quality of life for any of the three groups. Although the
results were inconclusive, they suggest that aromatherapy has
potential to treat knee pain in addition to standard care [].
3.1.5. Menstrual Pain. Menstrual pain is extremely common,
aecting –% of women worldwide []. In about %
of adolescents and young women, menstrual pain is severe
and may impair women from attending work, school, playing
sports, or enjoying other activities []. In one study, the
menstrual pain of women being treated with aromatherapy
abdominal massage was compared with a control group
of women treated with acetaminophen. e aromatherapy
group reported a signicantly higher rate of relief than
the acetaminophen group. e results, however, are unclear
because it is possible that massage alone could alleviate men-
strual pain []. A later randomized blind placebo clinical
trial remediated this by comparing an aromatherapy group
with a placebo group, receiving massage with no therapeutic
oil. In this study, the aromatherapy group reported a consid-
erable improvement in pain compared to the control [].
3.1.6. Pain Related to Labor and Childbirth. Despite being a
natural process, labor and childbirth is an extremely painful
process. Many women are fearful and anxious about the pain,
andthisanxietyisacommonreasonforelectivecesarean
sections. Surgical interventions increase the risk of childbirth
complications such as infection, hemorrhage, and thrombosis
emboli. Because many women are concerned about the eects
of pain medication on themselves and their infants during
childbirth, natural deliveries are becoming increasingly more
common []. In addition to managing pain, aromatherapy
during labor and delivery may also decrease nausea, vomit-
ing, headaches, hypertension, and pyrexia []. As a result,
aromatherapy is becoming a frequently requested nonmed-
ical method of managing pain and promoting relaxation. A
further benet of aromatherapy during labor and delivery
is that it decreases the use of medical pain interventions,
reducingthecostofcare[].Itisestimatedthatoering
aromatherapytowomeninlaborwouldcostapproximately
 per year in a center with , births per year [].
Using aromatherapy to manage pain related to childbirth
has been researched more than any other specic type of
pain. Despite the availability of data, results are inconclusive.
A review of two randomized controlled trials involving
more than  women found no dierence in pain inten-
sity, rate of cesarean section, or frequency of requests for
pharmacological intervention for women being treated with
clary sage, chamomile, lavender, ginger oil, or lemongrass
compared to women receiving standard care []. A semi-
experimental clinical trial found that women who were
treated with lavender aromatherapy during labor reported
alowerintensityofpainthanwomeninacontrolgroup.
Unfortunately, the aromatherapy group did not experience
a reduced duration of labor or improved Apgar scores of
their infants []. A similar study using orange oil for pain
management during labor and delivery reported comparable
results []. Although conicting reports exist, the low cost,
ease of use, and noninvasive approach makes aromatherapy
a viable option for complementary care during labor and
childbirth.
3.1.7. Post-Cesarean Section Pain. Pain is a common com-
plaint aer any surgery. Safe and eective pain aer cesarean
section is very important to the physical and mental well-
being of both mother and baby. A single blind clinical trial
found that lavender aromatherapy was eective in reducing
pain aer cesarean section []. A triple blind, randomized
placebo-controlledtrialfoundthesameresultsandalso

Pain Research and Treatment 
found that the lavender group reported a % satisfaction
rate with their treatment, compared to % in the placebo
group. Although heart rate was the same in both groups,
the lavender group experienced less nausea and dizziness
than the placebo group []. Both studies concluded that
although lavender aromatherapy can eectively reduce pain
aer cesarean section, the serious nature of surgery indicates
that aromatherapy should be used as part of a multimodal
pain management routine.
3.1.8. Episiotomy Pain. Episiotomy is a common obstetrical
procedure around the world, used successfully to prevent
lacerations and trauma during vaginal childbirth. A sitz
bath is a common treatment recommended by midwives.
Aclinicaltrialthatcomparedaconventionalsitzbathwith
use of sitz bath containing lavender found that the lavender
treatment did not reduce pain but did reduce inammation
and redness []. A separate study, however, found that
women who used lavender to manage episiotomy pain used
fewer analgesics for pain management during the same time
period [].
3.1.9. Postoperative Pain. Pain is common aer almost any
surgical procedure. Although analgesic medications are eec-
tive in reducing pain and nausea, uncomfortable side eects
can prolong the healing process and increase hospitalization
time []. In a randomized control study to examine pain
management aer total knee replacement surgery, patients
treated with eucalyptus aromatherapy experienced signif-
icantly lower pain and blood pressure than the control
group []. A study that examined lavender aromatherapy
in patients recovering from breast biopsy surgery found
that the aromatherapy group reported a signicantly higher
satisfaction with pain management than the control group,
even though rates of pain, narcotic use, and discharge time
were the same [].
3.1.10. Hemiplegic Shoulder Pain. As many as % of patients
who experience complete paralysis of half the body aer
stroke, a condition known as hemiplegia, complain of shoul-
der pain. Hemiplegic shoulder pain (HSP) is usually caused
by muscle weakness, subluxation, and decreased motor
strength. HSP is commonly treated with pharmacological
interventions, but the side eects are oen unpleasant and
dangerous. Nonpharmacological treatments, such as exercise,
massage, and biofeedback can reduce pain but are not
always eective. A  pilot study examined the benets of
lavender, rosemary, and peppermint oils on relieving HSP.
e experimental treatment group received aromatherapy
acupressure for  minutes twice a day to manage HSP. e
pain levels of the treatment group were compared to a control
group who received acupressure only without aromatherapy.
Although pain was reduced in both groups, the aromatherapy
group reported a % reduction in pain, compared to %
reduction in pain for the control group [].
3.1.11. Pediatric Pain. Treatment of pediatric pain can be
complicated. Sedatives and opioids, which are appropriate
medications for adults, can impact brain development in
young children []. Severe pain in pediatric patients is oen
associated with restricted food and liquid intake, which can
cause dehydration []. Additionally, many young children
areunabletoaccuratelydescribetheirpaintocaretakers.
Children being treated for serious illness oen experience
distress not directly related to their illness; therefore a holistic
approach to care is an integral part of treatment []. In
a study that treated infants with lavender aromatherapy for
pain associated with blood draw, infants in the aromatherapy
group were soothed faster than infants in the control group,
even though there was no dierence in pain during blood
draw []. In a study of children recovering from tonsil-
lectomy, children treated with lavender aromatherapy slept
better and required % less acetaminophen than children
in the control group []. A study of children who under-
went craniofacial surgery, however, found that aromatherapy
oered no benet. e researchers assert that several reasons,
including the children being afraid of strangers massaging
them, and massage given too soon aer general anesthesia
maybetoblame[].
3.1.12. Hospice and Cancer Pain. Complementary therapies,
such as aromatherapy, are becoming increasingly common
in palliative care and cancer treatment units. Nearly three-
quarters of UK hospitals oer aromatherapy or massage to
hospice and cancer patients. Although few quality studies
exist, aromatherapy is believed to reduce pain, anxiety,
anddepressionaswellasincreaseoverallsenseofwell-
being. ese attributes, in addition to low cost and easy
application, make it a viable option for increasing comfort
and reducing the use of pain medications []. Boehm et
al. conducted a meta-analysis of  studies examining the
eects of aromatherapy on the anxiety, depression, sleep,
pain, and overall well-being of cancer patients. Overall,
the study concluded that aromatherapy provides short-term
benets to cancer patients. However, many of the studies in
the meta-analysis found no signicant dierence between the
aromatherapy and control group. e poor quality of study
design, inadequate control interventions, and inconsistent
essential oil quality and type created limitations for the study
[]. Similarly, a randomized controlled study involving 
homecare hospice patients diagnosed with cancer concluded
that patients treated with lavender oil and with placebo
both reported improved symptoms, compared to the control
group. Interestingly, only members of the lavender group
chose to continue treatment aer the study []. A third
study was unable to report signicant long-term benets of
aromatherapy or massage alone in reducing anxiety or pain.
However, this study found statistically signicant improve-
ments to sleep scores and depression reduction [].
3.1.13. Hemodialysis Pain. By the year , nearly three-
quarter million Americans will undergo hemodialysis to treat
chronic renal failure. Successful treatment requires almost
daily needle insertion into a stula, which creates pain,
stress, and anxiety. Pain reduction is necessary to ensure that
patients are compliant with treatment. Because of the low cost
andeaseofadministrationassociatedwitharomatherapy,
it is a viable option for reducing needle insertion pain. A

Pain Research and Treatment
randomized control trial concluded that lavender aromather-
apy signicantly reduced pain and anxiety in hemodialysis
patients [].
3.1.14. Renal Colic. Renal colic, characterized by severe
abdominal and groin pain, is a common condition treated
in emergency rooms. Because pain is the presenting prob-
lem, narcotics or opiates are oen used immediately. In a
double-blind, randomized, placebo-controlled interventional
studies, patients diagnosed with renal colic were treated with
conventional therapy or with conventional therapy combined
with rose oil in a vaporizer. e aromatherapy group reported
signicantly less pain  minutes aer treatment than the
control group [].
3.1.15. Guillain Barre Syndrome. Guillain Barre Syndrome
(GBS) is characterized by sudden paralysis. e paralysis can
last as long as  weeks before spontaneous recovery begins.
Because the paralysis attacks the entire body, a quarter of
patients require assisted ventilation. e majority of patients
experience a full recovery in – months. Complications,
such as sinus tachycardia, hypotension, and infection, can
prolong recovery and in extreme cases lead to death in about
% of patients [].
e majority of patients contract GBS following a respi-
ratory or gastrointestinal tract infection. However, GBS can
also be triggered by surgeries, HIV, and hepatitis. Fortunately,
GBS can be successfully treated. e most common treatment
today is intravenous immunoglobulin (IVIG). IVIG treat-
ment is eective in boosting the body’s antibody response
with minimal complications. A serious drawback to the
treatment is that it is painful. GBS patients experiencing facial
paralysis are oen unable to express their level of distress.
Opiate medications are frequently used to manage pain and
discomfort during IVIG [].
3.1.16. Multiple Sclerosis Pain. Multiple sclerosis (MS) is a
serious neurological disorder involving myelin loss in the
central nervous system and inammation throughout the
body. Symptoms include fatigue, gastrointestinal discomfort,
bladder control problems, spasms, and visual disturbances.
ree-quarters of MS patients complain of chronic pain.
Because MS pain is not relieved easily by conventional
methods, many patients believe they must live with it. e
discomfort of MS, along with the stress of living with a
serious illness, can also cause anxiety and depression [].
A qualitative study examined the benets of aromatherapy
massage on  patients suering from MS pain. e site of the
massage varied based on the pain location of each individual
patient, and each patient had a single aromatherapy massage
session each month over the course of four months. At the
end of the study, most participants said they found it helpful,
and % chose to continue the therapy. % of the patients
reported and improved sense of overall well-being, %
reported improved relaxation, and % reported better sleep.
Overall, pain medication was reduced by % []. Although
this study provides exciting possibilities for the treatment of
MS pain, it is limited by its absence of control group. It is
Funnel plot with pseudo 95% condence limits
s.e. of mean di
−20 −15 −10 −5 0
Mean di
0.8
0.6
0.4
0.2
0
F : Publication bias funnel plot. A funnel plot was used
to assess risk of publication bias. A symmetrical funnel plot is an
indicator for lack of bias in a meta-analysis. A funnel plot loses its
utility with a cut-o of  studies and this analysis included only .
e funnel plot for this nal analysis was not fully symmetrical, but
publication bias cannot be concluded based on the small sample size
and heterogeneity of studies. e diagonal lines represent the limits
of % condence. Because strict % limits are not reported, they
are referred to as “pseudo % condence limits.”
impossible to determine from this study whether the benet
was from the aromatherapy or the massage.
3.2. Meta-Analysis
3.2.1. Characteristics of Included Studies.  studies were inc-
luded in the meta-analysis. Of these studies,  examined
inammatory pain conditions,  examined nociceptive pain
conditions,  studies examined chronic pain conditions, 
examined acute pain conditions,  studies examined post-
operative pain, and  studies focused on the treatment of
obstetrical and gynecological pain. Table  summarizes the
methods and ndings for each of the included studies,
organized alphabetically by authors’ last name.
3.2.2. Publication Bias. A funnel plot was used to assess risk
of publication bias (see Figure ). A symmetrical funnel plot
is an indicator for lack of bias in a meta-analysis. However
there can be many causes for funnel asymmetry including
heterogeneity of studies and a small number of included
studies. It is said that a funnel plot particularly loses its utility
with a cut-o of  studies [], and this analysis included
only . e funnel plot for this nal analysis was not fully
symmetrical, but publication bias cannot be concluded based
on the small sample size and heterogeneity of studies.
3.2.3. Primary Outcome Measure. Twelv e stud ies wit h a total
of , patients were included in the nal analysis. e
results suggest that the reduction in pain associated with
aromatherapy is statistically signicant (SMD = −., %
CI: −., −.; 𝑝 < 0.0001). Adhering to Cohen’s standards,
this indicates a large eect size. Heterogeneity was high (𝐼2=
96.6). e results of these studies are summarized in Figure .

Pain Research and Treatment 
T : Studies included in analysis. A summary of the studies included in analysis. CRP = C-reactive protein; VAS = visual analog score;
WBC = white blood count.
Study Study design Participants
(diagnosis, 𝑛)Intervention Comparison Summary of results
Ayan et al., 
Randomized
controlled trial,
double blind
Renal colic, 
Rose oil in
vaporizer and
conventional
treatment
Placebo and
conventional
treatment
ere was no statistically signicant
dierence between the starting VAS
values of the two groups, but the
VAS values  or  minutes aer
the initiation of therapy were
statistically lower in the group that
received conventional therapy plus
aromatherapy.
Bagheri-Nesami et
al., 
Randomized
controlled trial Hemodialysis, 
Inhaled lavender
oil during
hemodialysis
treatment
Placebo
e mean VAS pain intensity score
in the experimental and control
groups before the intervention was
. + . and . + .,
respectively (𝑝 = 0.35). e mean
VASpainintensityscoreinthe
experimental and control groups
aer three aromatherapy sessions
was . + . and . + .,
respectively (𝑝 = 0.009).
Hadi and Hanid,

Clinical trial, single
blind
Cesarean section,

Lavender oil in face
mask with oxygen Placebo
e aromatherapy group
experienced a signicant decrease
in pain compared to the control
group.
Jun et al.,  Randomized
controlled trial
Postoperative knee
replacement, 
Inhalation of
eucalyptus on
gauze
Placebo
Pain VAS on all three days
(𝑝 < 0.001) and systolic (𝑝 < 0.05)
and diastolic (𝑝 = 0.03) blood
pressure on the second day were
signicantly lower in the group
inhaling eucalyptus than that
inhaling almond oil. Heart rate,
CRP, and WBC, however, did not
dier signicantly in the two
groups.
Kaviani et al.,  Clinical trial,
semi-experimental Labor pain, 
Lavender oil on
swab attached to
patient
Placebo
e mean of pain intensity
perception in the aroma group was
lower than that of the control group
at  and  minutes aer the
intervention (𝑝 < 0.001).
Martin,  [] Randomized
controlled trial
Hand in ice water,

Lemoninoil
diuser
Machine oil in
diuser, no odor
Individuals exposed to both odors
reported signicantly greater pain
than did those in the control
condition at  minutes. At 
minutes, individuals exposed to the
unpleasant odor experienced
greater pain than did the control
group.
Marzouk et al.,

Randomized
controlled trial Menstrual pain, 
Abdominal
aromatherapy
massage
Abdominal
massage only
During both treatment phases, the
level and duration of menstrual
pain and the amount of menstrual
bleeding were signicantly lower in
the aromatherapy group than in the
placebo group.
Ou et al.,  []
Randomized
controlled trial,
double-blind
Menstrual pain, 
Self-massage with
lavender, clary
sage, and
marjoram
Placebo
Pain was signicantly decreased
(𝑝 < 0.001) aer one menstrual
cycle intervention in the two
groups.edurationofpainwas
signicantly reduced from . to .
days aer aromatherapy
intervention in the essential oil
group.

Pain Research and Treatment
T  : C ontinu e d .
Study Study design Participants
(diagnosis, 𝑛)Intervention Comparison Summary of results
Sheikhan et al.,

Randomized
controlled trial Episiotomy, 
Lavender oil in sitz
bath on eected
area
Tre a tmen t as usu a l
ere was a statistical dierence in
pain intensity scores between the 
groups aer  hours (𝑝 = 0.002),
and  days (𝑝 < 0.0001)aer
episiotomy. However, dierences in
pain intensity between the two
groups, at  hours aer surgery,
were not signicant (𝑝 = 0.066).
Yip et al.,  Randomized
controlled trial Low back pain, 
Acupoint
stimulation for
relaxation with
electrode pads
followed by an
acupressure
massage
Tre a tmen t as usu a l
 sessions of acupoint stimulation
followed by acupressure with
aromatic lavender oil were an
eective method for short-term low
back pain relief.
Yip and Tse, 
[]
Experimental
study Neck pain,  Acupressure with
lavender oil Tre atmen t as usu a l
e baseline VAS for the
intervention and control groups
were . and . out of ,
respectively (𝑝 = 0.72). One month
aer the end of treatment,
compared to the control group, the
manual acupressure group had %
reduced pain intensity (𝑝 = 0.02).
Yip, 2004
Yip, 2006
Hadi and Hanid, 2011
Ou, 2012
Sheikhan et al., 2012
Ayan et al., 2013
Jun et al., 2013
Marzouk et al., 2013
Kaviani et al., 2014
Namazi et al., 2014
D+L overall
with estimated predictive interval
Bagheri-Nesami et al., 2014
Martin, 2006
−1.26 (−1.87, −0.66)
0.72 (0.08, 1.36)
−0.42 (−1.19, 0.35)
−2.00 (−2.34, −1.66)
0.21 (−0.36, 0.77)
−0.92 (−1.45, −0.39)
−1.61 (−2.12, −1.11)
−17.70 (−21.22, −14.19)
0.08 (−0.32, 0.48)
−3.80 (−4.49, −3.11)
−0.81 (−1.13, −0.49)
−3.45 (−4.04, −2.87)
−1.18 (−1.33, −1.03)
−1.78 (−2.62, −0.95)
— (−5.08, 1.51)
27, 0.61 (0.31)
20, 6.44 (2.55)
17, 0.77 (0.51)
100, 0.67 (0.85)
24, 3.92 (2.39)
30, 2.7 (1.74)
40, 1.08 (1.07)
25, 3.8 (0.02)
48, 4.1 (2.6)
46, 2.36 (0.25)
80, 6.9 (2.3)
57, 7.75 (0.56)
514
24, 0.99 (0.29)
20, 4.76 (2.11)
11, 0.98 (0.48)
100, 4.05 (2.23)
24, 3.46 (2.04)
30, 4.23 (1.59)
40, 3.75 (2.08)
27, 5.1 (0.1)
47, 3.9 (2.4)
46, 3.43 (0.31)
80, 8.5 (1.6)
56, 9.46 (0.534)
505
5.84
5.19
3.62
18.40
6.62
7.50
8.31
0.17
13.16
4.48
20.49
6.22
100.00
−21.2 0 21.2
Aromatherapy Control
Study ID SMD (95% CI) N, mean
(SD); treatment
N, mean
(SD); control
%
weight
(I–V)
I–V overall(I2= 96 .6%, p = 0.000)
F : Forest plot: results of all included studies. is forest plot summarizes the results of all included studies. e numbers on the 𝑥-axis
measure treatment eect. e gray squares represent the weight of each study. e larger the sample size, the larger the weight and the size of
gray box. e small black boxes with the gray squares represent the point estimate of the eect size and sample size. e black lines on either
side of the box represent a % condence interval.

Pain Research and Treatment 
Study ID
Inammatory
Yip, 2004
Yip, 2006
Ou, 2012
Ayan et al., 2013
Marzouk et al., 2013
SMD (95% CI) N, mean
(SD); treatment
N, mean
(SD); control
%
weight
(I–V)
I–V subtotal (I2= 89.7%, p = 0.000)
D+L subtotal
with estimated predictive interval
I–V subtotal (I2= 97.5%, p = 0.000)
D+L subtotal
with estimated predictive interval
with estimated predictive interval
Nociceptive
Martin, 2006
Hadi and Hanid, 2011
Sheikhan et al., 2012
Jun et al., 2013
Bagheri-Nesami et al., 2014
Kaviani et al., 2014
Namazi et al., 2014
Heterogeneity between groups:p = 0.000
−21.2 0 21.2
Aromatherapy Control
−1.26 (−1.87, −0.66)
−0.42 (−1.19, 0.35)
0.21 (−0.36, 0.77)
−1.61 (−2.12, −1.11)
0.08 (−0.32, 0.48)
−0.53 (−0.77, −0.29)
27, 0.61 (0.31)
17, 0.77 (0.51)
24, 3.92 (2.39)
40, 1.08 (1.07)
48, 4.1 (2.6)
156
−0.60 (−1.36, 0.16)
— (−3.49, 2.29)
0.72 (0.08, 1.36)
−2.00 (−2.34, −1.66)
−0.92 (−1.45, −0.39)
−17.70 (−21.22, −14.19)
−3.80 (−4.49, −3.11)
−0.81 (−1.13, −0.49)
−3.45 (−4.04, −2.87)
−1.57 (−1.76, −1.39)
20, 6.44 (2.55)
100, 0.67 (0.85)
30, 2.7 (1.74)
25, 3.8 (0.02)
46, 2.36 (0.25)
80, 6.9 (2.3)
57, 7.57 (0.56)
358
514
24, 0.99 (0.29)
11, 0.98 (0.48)
24, 3.46 (2.04)
40, 3.75 (2.08)
47, 3.9 (2.4)
146
20, 4.76 (2.11)
100, 4.05 (2.23)
30, 4.23 (1.59)
27, 5.1 (0.1)
46, 3.43 (0.31)
80, 8.5 (1.6)
56, 9.46 (0.534)
359
15.55
9.64
17.62
22.14
35.04
100.00
8.31
29.46
12.01
0.28
7.18
32.80
9.96
100.00
505 —
−2.88 (−4.17, −1.58)
— (−7.46, 1.71)
−1.18 (−1.33, −1.03)
−1.78 (−2.62, −0.95)
— (−5.08, 1.51)
D+L overall
I–V overall(I2= 96.6%, p = 0.000)
F : Forest plot: nociceptive versus inammatory pain. is forest plot summarizes the results of nociceptive pain studies and
inammatory pain studies. e numbers on the 𝑥-axis measure treatment eect. e gray squares represent the weight of each study. e
larger the sample size, the larger the weight and the size of gray box. e small black boxes with the gray squares represent the point estimate
of the eect size and sample size. e black lines on either side of the box represent a % condence interval.
3.2.4. Secondary Outcomes Measures
Nociceptive versus Inammatory Pain. Five of the eligible
studies used aromatherapy to treat inammatory pain, while
seven studies examined nociceptive pain. Subgroup analyses
indicated that the ecacy of aromatherapy was more consis-
tent for nociceptive pain (SMD = −., % CI: −., −.,
𝑝 < 0.0001) than for inammatory pain (SMD = −., %
CI: −., −., 𝑝 < 0.0001), although the eect size was
large for both. Heterogeneity was high for nociceptive (𝐼2=
97.5) pain and moderately high (𝐼2= 89.7) for inammatory
pain. e results of these studies are summarized in Figure .
Acute Pain versus Chronic Pain. Four of the included studies
examined the use of aromatherapy in treating chronic pain,
while eight examined acute pain. Subgroup analyses indi-
cated a large positive eect of aromatherapy on acute pain
(SMD = −., % CI: −., −., 𝑝 < 0.0001)butonly
a small positive eect on chronic pain conditions (SMD =
−., % CI: −., ., 𝑝 = 0.001). Heterogeneity was
high for acute (𝐼2= 97.2) pain and moderately high (𝐼2=
81.3) for chronic pain. e results of these studies are
summarized in Figure .
Postoperative Pain. ree studies examined the eect of aro-
matherapy in managing postoperative pain, while  studies
focused on pain not related to surgical procedures. Subgroup
analyses found a signicant positive eect of aromatherapy
onpostoperativepain(SMD=−., % CI: −., −.,
𝑝 < 0.0001) and nonpostoperative pain (SMD = −., %
CI: −., −., 𝑝 < 0.0001). Heterogeneity was high (𝐼2=
97.8). e results of these studies are summarized in Figure .
Obstetrical and Gynecological Pain. Aromatherapy is com-
monly used to manage pain related to menstruation and
childbirth. erefore, these subjects are researched more
oen than many other types of pain. Six studies included
in this analysis examined the benets of aromatherapy in
treating obstetrical and gynecological pain. A signicant
positive eect was found in these studies (SMD = −., %
CI: −., −., 𝑝 < 0.0001). Heterogeneity was high (𝐼2=
96.6). e results of these studies are summarized in Figure .
4. Discussion
Despite being one of the most common complaints of patients
in any healthcare setting, pain is extremely subjective and
may be dicult for patients to communicate. A holistic
approach to pain management takes into consideration the
emotional responses, cultural beliefs, cognitive interpreta-
tion, and personal history of the patient, in addition to
thephysiologicaspectsofpain[].isstudyfoundthat
aromatherapy can be eective in treating pain for a variety

 Pain Research and Treatment
−21.2 0 21.2
Aromatherapy Control
Study ID SMD (95% CI) N, mean
(SD); treatment
N, mean
(SD); control
%
weight
(I–V)
Chronic
Yip, 2004
Yip, 2006
Ou, 2012
Marzouk et al., 2013
I–V subtotal (I2= 81.3%, p = 0.001)
D+L subtotal
with estimated predictive interval
I–V subtotal (I2= 97.1%, p = 0.000)
D+L subtotal
with estimated predictive interval
D+L overall
with estimated predictive interval
Heterogeneity between groups:p = 0.000
I–V overall(I2= 96.6%, p = 0.000)
Martin, 2006
Hadi and Hanid, 2011
Sheikhan et al., 2012
Ayan et al., 2013
Jun et al., 2013
Bagheri-Nesami et al., 2014
Kaviani et al., 2014
Namazi et al., 2014
Acute
−1.26 (−1.87, −0.66)
−0.42 (−1.19, 0.35)
0.21 (−0.36, 0.77)
0.08 (−0.32, 0.48)
−0.22 (−0.49, 0.05)
27, 0.61 (0.31)
17, 0.77 (0.51)
24, 3.92 (2.39)
48, 4.1 (2.6)
116
−0.33 (−0.99, 0.33)
— (−3.28, 2.62)
0.72 (0.08, 1.36)
−2.00 (−2.34, −1.66)
−0.92 (−1.45, −0.39)
−17.70 (−21.22, −14.19)
−1.61 (−2.12, −1.11)
−3.80 (−4.49, −3.11)
−0.81 (−1.13, −0.49)
−3.45 (−4.04, −2.87)
−1.58 (−1.75, −1.40)
20, 6.44 (2.55)
100, 0.67 (0.85)
30, 2.7 (1.74)
25, 3.8 (0.02)
40, 1.08 (1.07) 40, 3.75 (2.08)
46, 2.36 (0.25)
80, 6.9 (2.3)
57, 7.57 (0.56)
398
514
24, 0.99 (0.29)
11, 0.98 (0.48)
24, 3.46 (2.04)
47, 3.9 (2.4)
106
20, 4.76 (2.11)
100, 4.05 (2.23)
30, 4.23 (1.59)
27, 5.1 (0.1)
46, 3.43 (0.31)
80, 8.5 (1.6)
56, 9.46 (0.534)
399
19.97
12.39
22.64
45.01
100.00
26.00
7.34
10.60
11.75
0.24
6.33
28.95
8.79
100.00
505
−2.62 (−3.73, −1.51)
— (−6.58, 1.34)
−1.18 (−1.33, −1.03)
−1.78 (−2.62, −0.95)
— (−5.08, 1.51)
—
F : Forest plot: acute versus chronic pain. is forest plot summarizes the results of acute pain studies and chronic pain studies. e
numbers on the 𝑥-axis measure treatment eect. e gray squares represent the weight of each study. e larger the sample size, the larger
the weight and the size of gray box. e small black boxes with the gray squares represent the point estimate of the eect size and sample size.
e black lines on either side of the box represent a % condence interval.
Study ID SMD (95% CI) N, mean
(SD); treatment
N, mean
(SD); control
Not postoperative pain
Yip, 2004
Martin, 2006
−1.26 (−1.87, −0.66 )
0.72 (0.08, 1.36)
−0.42 (−1.19, −0.3 5)
0.21 (−0.36, 0.77)
−1.61 (−2.12, −1.11)
0.08 (−0.32, 0.48)
−3.80 (−4.49, −3.11)
−0.81 (−1.13, −0.4 9)
−3.45 (−4.04, − 2.87)
−0.96 (−1.13, −0.7 9)
−1.15 (−2.05, −0.24 )
— (−4.52, 2.22)
−2.00 (−2.34, −1.66 )
−0.92 (−1.45, − 0.39)
−17.70 (−21.22, −14.19)
−1.79 (−2.08, −1.51)
−5.16 (−7.76, −2.5 7)
— (−36.94, 26.61)
−1.18 (−1.33, −1.03 )
−1.78 (−2.62, −0.9 5)
— (−5.08, 1.51)
Yip, 2006
Ou, 2012
Ayan et al., 2013
Marzouk et al., 2013
Bagheri-Nesami et al., 2014
Kaviani et al., 2014
Namazi et al., 2014
I–V subtotal (I2= 96.3 %, p = 0.000)
D+L subtotal
with estimated predictive interval
D+L subtotal
with estimated predictive interval
D+L overall
with estimated predictive interval
Postoperative pain
Hadi and Hanid, 2011
Sheikhan et al., 2012
Jun et al., 2013
I–V subtotal (I2= 97.8%, p = 0.000)
Heterogeneity between groups:p = 0.000
I–V overall(I2= 96.6%, p = 0.000)
−21.2 0 21.2
Aromatherapy Control
27, 0.61 (0.31)
20,6.44 (2.55)
17, 0.77 (0.51)
24,3.92 (2.39)
40,1.08 (1.07)
48,4.1 (2.6)
46,2.36 (0.25)
80,6.9 (2.3)
57,7.57 (0.56)
359
100, 0.67 (0.85)
30,2.7 (1.74)
25,3.8 (0.02)
155
514
24, 0.99 (0.29)
20,4.76 (2.11)
11, 0.98 (0.48)
24,3.46 (2.04)
40,3.75 (2.08)
47,3.9 (2.4)
46,3.43 (0.31)
80,8.5 (1.6)
56,9.46 (0.534)
348
100,4.05 (2.23)
30,4.23 (1.59)
27,5.1 (0.1)
157
505
%
Weight
(I–V)
7.90
7.02
4.90
8.95
11.24
17.80
6.06
27.71
8.42
100.00
70.57
28.76
0.66
100.00
—
F : Forest plot: postoperative pain. is forest plot summarizes the results of postoperative pain studies. e numbers on the 𝑥-axis
measure treatment eect. e gray squares represent the weight of each study. e larger the sample size, the larger the weight and the size of
gray box. e small black boxes with the gray squares represent the point estimate of the eect size and sample size. e black lines on either
side of the box represent a % condence interval.

Pain Research and Treatment 
— (−5.08, 1.51)
−1.18 (−1.33, −1.03)
−2.00 (−2.34, −1.66)
−3.02 (−4.79, −1.26)
−1.40 (−1.68, −1.12)
−3.80 (−4.49, −3.11)
−17.70 (−21.22, −14.19)
−1.61 (−2.12, −1.11)
−0.42 (−1.19, 0.35)
0.72 (0.08, 1.36)
−1.26 (−1.87, −0.66)
−0.92 (−1.45, −0.39)
−0.81 (−1.13, −0.49)
−3.45 (−4.04, −2.87)
−1.10 (−1.27, −0.92)
−1.14 (−2.10, −0.19)
— (−4.65, 2.36)
— (−9.38, 3.34)
0.21 (−0.36, 0.77)
0.08 (−0.32, 0.48)
−1.78 (−2.62, −0.95)
514 505 —
100.00
100.00
16.23
0.63
30.10
13.11
18.80
21.13
8.59
28.30
18.18
10.36
9.14
25.42
168175
100, 4.05 (2.23)100, 0.67 (0.85)
24, 3.92 (2.39)
30, 2.7 (1.74)
48, 4.1 (2.6)
80, 6.9 (2.3)
57, 7.57 (0.56)
24, 3.46 (2.04)
24, 0.99 (0.29)
20, 4.76 (2.11)
11, 0.98 (0.48)
40, 3.75 (2.08)
46, 3.43 (0.31)46, 2.36 (0.25)
40, 1.08 (1.07)
25, 3.8 (0.02)
27, 0.61 (0.31)
SMD (95% CI) (SD); treatment (SD); control
20, 6.44 (2.55)
17, 0.77 (0.51)
27, 5.1 (0.1)
30, 4.23 (1.59)
47, 3.9 (2.4)
80, 8.5 (1.6)
56, 9.46 (0.534)
337339
N, mean N, mean
Not obstetrical-gynecologic pain
Obstetrical-gynecologic pain
Yip, 2004
Martin, 2006
Yip, 2006
Ayan et al., 2013
Marzouk et al., 2013
Bagheri-Nesami et al., 2014
Kaviani et al., 2014
Namazi et al., 2014
I–V subtotal (I2= 97.2%, p = 0.000)
I–V subtotal (I2= 96.6%, p = 0.000)
D+L subtotal
with estimated predictive interval
D+L subtotal
with estimated predictive interval
Hadi and Hanid, 2011
Sheikhan et al., 2012
Jun et al., 2013
D+L overall
with estimated predictive interval
Heterogeneity between groups:p = 0.068
I–V overall(I 2= 96.6 %, p = 0.000)
Ou, 2012
Study ID
%
weight
(I–V)
Control
0
−21.2 21.2
Aromatherapy
F : Forest plot: obstetrical and gynecological pain. is forest plot summarizes the results of obstetrical and gynecological pain studies.
e numbers on the 𝑥-axis measure treatment eect. e gray squares represent the weight of each study. e larger the sample size, the larger
the weight and the size of gray box. e small black boxes with the gray squares represent the point estimate of the eect size and sample size.
e black lines on either side of the box represent a % condence interval.
of medical conditions. Likewise, most studies found that
patient satisfaction was increased, while patient anxiety and
depression were decreased. Still, the reasons for these results
are unclear. A likely possibility is that satisfaction with pain
management oen has little correlation to pain reduction and
is more oen associated with communication, sta behavior,
and empathy []. is need within the practice of pain
management is easily fullled by the use of aromatherapy. For
one, the touch and attention associated with aromatherapy
massage can be benecial. Massage is typically relaxing and
enjoyable for people experiencing many types of pain. In
addition to the physical benets associated with aromather-
apy,apleasantscentmayplayakeyroleinpatientsatisfaction.
Most participants who received aromatherapy treatment had
the benet of special treatment sessions outside of normal
treatment protocol. e results of this analysis, combined
with the ndings in the systematic review, indicate that
aromatherapy can be benecial in treating pain when com-
bined with standard pain management protocol. It is also
less expensive and has fewer side eects than traditional pain
management drugs.
5. Study Limitations
e results of this study were impacted by several study
limitations. For one, no uniform measure of pain exists. Only
studies using VAS were included, which meant that some
potentially strong studies needed to be eliminated. Addition-
ally, some studies with robust research designs failed to report
pertinent information, such as postintervention sample size
or mean dierence. Data for other studies was complicated
by poor study design, absence of control, or measurements of
multiple conditions within a single scale. is study was able
to examine the ecacy of aromatherapy for treating nocicep-
tive and inammatory pain, but no eligible studies examined
the ecacy of aromatherapy for treating neuropathic or
functional pain. Additionally, the  studies included in the
nal pooled analysis examined treatment of  dierent pain
conditions, using varying methods of aromatherapy in the
intervention, diering essential oils, and inconsistent control
therapies. Because the included studies were conducted in
several countries around the world, the cultural attitudes of
participants towards aromatherapy must also be considered.
Of course, not all patients are equally accepting physical
touch. Individual preference, cultural norms, physical illness,
or psychological makeup may contribute to touch aversion.
Further research is needed to understand the true potential
of aromatherapy for pain management.
6. Conclusion
is study found a signicant positive eect of aromatherapy
in reducing pain. ese results indicate that aromatherapy

 Pain Research and Treatment
should be considered a safe addition to current pain man-
agement procedures as no adverse eects were reported in
any of the included studies. Additionally, the cost associated
with aromatherapy is far less than the cost associated with
standard pain management treatment. Although the present
meta-analysis indicates a large positive eect for the use
of aromatherapy for pain management, the sample size is
small. Given the prevalence of aromatherapy, more research is
necessary to fully understand clinical applications for its use.
Competing Interests
e authors declare that there is no conict of interests
regarding the publication of this paper.
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