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Rhinology, 46, 271-275, 2008
*Received for publication: March 19, 2008; accepted: June 3, 2008
INTRODUCTION
Acute rhinosinusitis associated with common cold and flu is one
of the most common diseases (1). Despite the widespread folk-
lore that hot drinks are an effective treatment for colds and flu,
and the use of hot drink formulations for many current com-
mon cold medicines, there appears to be no evidence base in
the medical literature supporting the efficacy of this common
treatment for common cold and flu. There are a few studies that
have investigated the effects of hot drink on nasal resistance and
other nasal functions in healthy subjects, but surprisingly, no
reports have been found in the literature on the effects of a hot
drink on common cold and flu symptoms. Martin et al. reported
that application of either cold (4-6°C) or warm water (44-52°C)
to the oral mucosa in healthy subjects caused an increase in
nasal airway resistance, but that application of tepid water (26-
28°C) did not alter nasal resistance (2). Saketkhoo et al. reported
that drinking hot water or soup (65°C) increased nasal mucus
velocity in healthy subjects, but did not change nasal airway
resistance (3). Recently, Lal et al. reported that ingestion of hot
water (82°C) decreases nasal cross sectional area as measured by
acoustic rhinometry in healthy subjects (4). With these contrast-
ing results from previous studies, and the fact that none of the
previous studies included any subject suffering from common
cold, the effects of hot drink when suffering from common cold
remains unclear.
The present study will investigate the effects of a hot drink or
similar drink at room temperature on nasal conductance as
measured by rhinomanometry, and on upper airway symptoms
measured by subjective scores, in patients suffering from com-
mon cold and flu.
MATERIALS AND METHODS
Subjects
Subjects that responded to an advertisement were screened by
the investigator to ensure they met the inclusion and exclusion
criteria for the study. Anterior rhinoscopy using a Thuddicum
speculum was performed to detect any gross nasal septal devia-
tion or the presence of nasal polyps. Those subjects eligible for
the study were randomly allocated to receive either a hot drink
or a drink at room temperature. The subjects enrolled in the
study were from the staff and student population of Cardiff
University. In order to qualify for entry to the study patients
had to be aged 18 years and above, suffering from symptoms
of common cold/flu like illness of less than 7 days duration,
suffering from at least three common cold symptoms (runny
nose, sneezing, blocked nose, sore throat, cough) and scoring
at least two symptoms as moderate on a four point ordinal
scale (0- not present, 1- mild, 2- moderate, 3- severe). Subjects
were excluded from the study if they were suffering from any
nasal disease (nasal polyps, chronic rhinitis, severe septal devi-
Hot drinks are a common treatment for common cold and flu but there are no studies reported
in the scientific and clinical literature on this mode of treatment. This study investigated the
effects of a hot fruit drink on objective and subjective measures of nasal airflow, and on subjec-
tive scores for common cold/flu symptoms in 30 subjects suffering from common cold/flu. The
results demonstrate that the hot drink had no effect on objective measurement of nasal airflow
but it did cause a significant improvement in subjective measures of nasal airflow. The hot
drink provided immediate and sustained relief from symptoms of runny nose, cough, sneezing,
sore throat, chilliness and tiredness, whereas the same drink at room temperature only provid-
ed relief from symptoms of runny nose, cough and sneezing. The effects of the drinks are dis-
cussed in terms of a placebo effect and physiological effects on salivation and airway secre-
tions. In conclusion the results support the folklore that a hot tasty drink is a beneficial treat-
ment for relief of most symptoms of common cold and flu.
Key words: hot drink, common cold, flu, nasal airflow, cough, sneezing, rhinomanometry
SUMMARY
The effects of a hot drink on nasal airflow and
symptoms of common cold and flu*
A. Sanu and R. Eccles
Common Cold Centre and Healthcare Clinical Trials, Cardiff School of Biosciences, Cardiff University, Cardiff,
United Kingdom
ORIGINAL CONTRIBUTION
82733_Sanu:and Eccles 12-11-2008 08:56 Pagina 271
272 Sanu and Eccles
ation) or other clinically significant disease, and if they had
taken any medication that could influence common cold symp-
toms, and if they had ingested any hot food or drink within the
previous hour.
Procedures
At baseline, subjects scored their subjective sensation of nasal
airflow and symptoms of common cold. Total nasal airway
resistance was measured by the technique of posterior rhino-
manometry. Within 10 minutes of these measurements the
subjects drank either a hot drink or one at room temperature.
The subjective scores and measurements of nasal airway resis-
tance were repeated immediately after finishing the drink and
at 15 minutes and 30 minutes after the drink.
Drink treatment
A commercially produced cordial drink (Robinsons Apple &
Blackcurrant) was used for this study. Twenty ml of cordial
was diluted with 80 ml of water to provide either a hot drink at
70°C (± 5°C) or a drink at room temperature (20°C ± 5°C).
Subjects were asked to slowly sip the drink until it was all
drunk, for up to a maximum of 10 minutes. The drink was
marketed as containing no added sugars and as a low-calorie
drink, and contained only 9 kcal or Calories per 100 ml of con-
centrate. The drink was purple in colour and had a distinctive
blackcurrant smell, especially in the hot drink, with a slightly
sweet and acidic flavour. Ingredients: water, fruit juices from
concentrate (apple 8%, blackcurrant 2%, citric acid, natural
colour (anthocyanins), acidity regulator (sodium citrate),
sweeteners (aspartame, saccharin), preservatives (potassium
sorbate, sodium metabisulphite) and natural flavouring.
Rhinomanometry
An NR6-2 rhinomanometer (GM instruments, Glasgow UK)
was used in this study to measure nasal resistance to airflow
using the technique of posterior rhinomanometry. The instru-
ment measured nasal airflow at a sample pressure of 75Pa.
Subjects breathed into a facemask whilst sealing their lips
around a pressure sensing tube in the oral cavity. For each
measurement of nasal airway resistance (NAR) two consecu-
tive sets of four respiratory cycles were obtained and the coeffi-
cient of variation (CV) of these two sets was calculated. If the
CV was 10% or less, the measurement was accepted and the
mean NAR of the 8 respiratory cycles was calculated. If the CV
was more than 10% then the respiratory cycle sets were dis-
carded and the procedure repeated until a CV of 10% or less
was achieved. If a CV less than 10% could not be obtained
after three attempts the data was entered as missing. The
results for rhinomanometry were expressed as conductance
rather than resistance in order to be able to include data from
subjects who were completely obstructed, as they would have a
conductance of zero, which can be handled in statistical analy-
sis, whereas a resistance of infinity could not be used in data
analysis. Subjects who presented with complete or almost
complete nasal obstruction were deemed to have a nasal con-
ductance of zero.
Subjective symptom scores
A 100 mm visual analogue scale (VAS) anchored by the
descriptors ‘nose feels extremely clear (0 mm) and ‘nose feels
extremely blocked’ (100 mm) was used to assess the sensation
of nasal airflow prior to each measurement of nasal airflow
with rhinomanometry. The scores represented the sensation of
nasal airflow at the time of measurement.
Common cold symptoms of runny nose, cough, sneezing, sore
throat, chilliness and tiredness were scored on VAS scales
anchored by the descriptors; no runny nose (0 mm) -worst
runny nose I can imagine (100 mm) etc. The scores represent-
ed the symptoms present at the time of assessment.
Sample size, statistics and efficacy variables
This was a pilot study and the size of the study population is
estimated from the results of previous studies on the effects of
hot drinks on nasal airway resistance. Because of differences in
measurements and study populations it was not possible to do
a formal power calculation. Martin and Tansy (2) used six sub-
jects, and Lal et al. (4) used eight healthy adults. In order to
allow for an increased variability in this study it was proposed
to use a population of thirty subjects (i.e. 15 subjects for each
type of drink).
The primary efficacy variable was pre-defined in the protocol
as the change in nasal conductance of airflow from before the
drink to immediately after the drink. Secondary efficacy vari-
ables were; change in subjective scores of nasal obstruction
and the symptoms of common cold from before the drink to
immediately after the drink, and at other time points.
The Statistical Package for the Social Sciences version 11
(SPSS 11) for the Macintosh platform was utilised for statistical
analysis. It was assumed that the data was not normally distrib-
uted and all data was analysed with the non-parametric
Wilcoxon signed ranks test.
Ethical approval and finance
The study was reviewed and approved by the South East
Wales Local Research Ethics Committee and conducted in
accordance with the International Conference of
Harmonization’s ‘Guidelines for Good Clinical Practice’ and
the World Medical Association’s ‘Declaration of Helsinki’. The
study was financed from the research funds of the Common
Cold Centre, Cardiff University and did not receive any com-
mercial sponsorship.
RESULTS
Subjects
A total of 38 subjects were screened for the study. Six subjects
failed to fulfil the inclusion/exclusion criteria and were exclud-
82733_Sanu:and Eccles 12-11-2008 08:56 Pagina 272
Hot drink and common cold symptoms 273
ed, and a further two subjects failed to complete the study,
leaving 30 protocol valid subjects with 15 subjects in each treat-
ment group. There were 21 females (70%) and nine males
(30%). The mean age of the study population was 20.8 years
(range 18 to 36 years).
Drinks
The mean temperature of the hot drink was 73.7°C (range
70,0°C to 75,0°C) and the mean temperature of the room tem-
perature drink was 21,8°C (range 21,0°C to 22,0°C). The mean
time taken to consume the hot drink was 5.2 minutes, and 1.4
minutes for the room temperature drink. All the subjects man-
aged to finish their drinks within the given 10 minutes.
Objective and subjective effects on nasal airflow
The effects of ingestion of the two drinks on the subjective
perception of nasal airflow are shown in Figure 1. The room
temperature drink caused a non-significant trend towards
scores for increased sensation of nasal airflow, whereas the hot
drink caused an immediate improvement in sensation of air-
flow that was sustained for 30 minutes.
The effects of ingestion of the two drinks on the objective
measure of conductance of nasal airflow are shown in Figure 2.
The room temperature drink caused significant trend of
decreased nasal airflow, whereas the hot drink did not cause
any significant changes in conductance.
Common cold symptoms
The effects of ingestion of the hot drink on common cold
symptom scores are shown in Figure 3. All of the six symp-
toms were decreased in severity after the hot drink with imme-
diate effects on cough, sore throat, chilliness and tiredness,
and relief at 15 minutes after the hot drink for runny nose and
20
25
30
35
40
45
50
55
60
0 5 10 15 20 25 30
Time Minutes
VAS score mm
0.005 0.027 0.011
ns
ns
ns
nose clear
nose blocked
Figure 1. Subjective scores for nasal airflow on 100mm visual analogue
scale, before and up to 30 minutes after drink. Open symbols drink at
room temperature; filled symbols hot drink. P values refer to compar-
isons with baseline score (ns = no significant difference from baseline).
Each point represents the median value of data from 15 subjects.
Figure 2. Conductance of nasal airflow, before and up to 30 minutes
after drink. Open symbols drink at room temperature; filled symbols
hot drink. P values refer to comparisons with baseline score (ns = no
significant difference from baseline). Each point represents the median
value of data from 15 subjects
0
10
20
30
40
50
60
runny nose cough sneezing sore throat chilliness tiredness
*
**
*
*
*
*
***
***
*
*
Figure 3. Effects of a hot fruit drink on common cold symptoms
scored on visual analogue scales (0 = no symptom, 100 = worst symp-
tom I can imagine). Each bar represents the median value of data from
15 subjects, for baseline, and 10, 15 and 30 minutes after the drink.
Statistically significant differences from baseline (p < 0.05) are indicat-
ed by an asterisk.
0
10
20
30
40
50
60
runny nose cough sneezing sore throat chilliness tiredness
*
**
*
*
**
Figure 4. Effects of a fruit drink at room temperature on common cold
symptoms scored on visual analogue scales (0 = no symptom, 100 =
worst symptom I can imagine). Each bar represents the median value
of data from 15 subjects, for baseline, and 10, 15 and 30 minutes after
the drink. Statistically significant differences from baseline (p < 0.05)
are indicated by an asterisk.
82733_Sanu:and Eccles 12-11-2008 08:56 Pagina 273
274 Sanu and Eccles
sneezing. The symptom relief was still significant for 30 min-
utes after the hot drink for all of the symptoms except tired-
ness.
The effects of ingestion of the room temperature drink on
common cold symptom scores are shown in Figure 4. In con-
trast to the overall relief of symptoms provided by the hot
drink, only three of the symptoms were relieved with the room
temperature drink; runny nose, cough and sneezing. There
were no significant changes in the symptom scores for sore
throat, chilliness and tiredness. The comparisons between
baseline score and the subjective scores after the drinks
involve multiple statistical comparisons and caution is neces-
sary when interpreting any individual result. However, the
magnitude of the responses and the number of statistically sig-
nificant differences (p < 0.05) do support the overall benefit of
the drinks in decreasing symptom severity.
DISCUSSION
The results demonstrate that ingestion of a hot drink does not
cause any significant change in nasal conductance but that it
does provide some subjective relief of nasal obstruction as
shown in Figure 1. The measures of nasal conductance (Figure
2) show an overall trend for a decrease in conductance or nasal
congestion. There is a small difference in the baseline levels of
nasal conductance, but this is unlikely to influence the results,
as the difference seems large because of the expanded scale of
the axis of the graph. The decrease in nasal conductance from
baseline is statistically significant (p < 0.05) in the group that
ingested the room temperature drink, and the lack of any sig-
nificant change in the hot drink group may be due to an initial
trend towards increased conductance immediately after the
drink that negated any effects of an overall trend towards con-
gestion. Decreases in nasal conductance have been observed in
studies on subjects with common cold when the subjects were
merely rested in the laboratory environment and not exposed
to any treatment (5). Clarke and Eccles reported a paradoxical
relationship between an objective decrease in conductance of
airflow (nose becoming more congested) and a subjective per-
ception of increased nasal airflow (nose decongesting) in sub-
jects with common cold when they were resting in a laboratory
environment for a period of up to 2 hours (5). A similar para-
doxical relationship between objective and subjective measures
of nasal obstruction has been reported in studies on nasal
decongestants (6). The slow trend towards nasal congestion in
resting subjects may be due to a decrease level of sympathetic
activity and decreased vasoconstrictor activity to the nasal blood
vessels. It is not understood why subjects score improved nasal
airflow even though the nose may be congesting. The paradoxi-
cal subjective improvement in nasal sensation of airflow does
not appear to be a placebo effect as it is still present when sub-
jects do not receive any type of treatment (5).
The results demonstrate that a hot fruit drink can provide sub-
jective relief from all the six symptoms of common cold that
were scored in this study. Ingestion of the same drink at room
temperature only provided relief for three of the symptoms.
This demonstrates the extra benefit provided by the increase
in drink temperature and supports the traditional use of hot
drinks to relieve common cold symptoms. There were some
base-line differences in symptom severity between the two
treatment groups, as with small group size it was not possible
to balance the severity of all symptoms at baseline. The base-
line symptom scores for sore throat and cough in the group
taking the room temperature drink were less than the baseline
scores in the group taking the hot drink. It is possible that if
the symptom scores for sore throat and cough had been higher
in the group taking the room temperature drink, then this
group may have also had some significant reduction in symp-
tom severity for these symptoms.
The drinks may provide symptom relief by a placebo effect
where the subject believes that the drink will provide relief due
to prevailing folklore (7). The symptom relief may also be due
to a ‘physiological’ effect of the drink where the taste, smell
and temperature of the drink may promote salivation and air-
way mucus secretions to lubricate and soothe the upper air-
ways. This demulcent effect of the drink may be more relevant
for symptoms such as cough (8) and sore throat.
The symptom results also show some unexpected benefits as
both the hot drink and the room temperature drink provided
relief from the symptoms of sneezing and runny nose. This
may be due to stimulation of branches of the trigeminal nerve
that supply both the oral and nasal cavities such as the major
palatine nerve (9).
This study may be criticised because it was not controlled with
a placebo and that the symptom relief is merely a placebo
effect. The benefit of a placebo effect should not be underesti-
mated as in most cough medicines it has been estimated to
provide at least 85% of the total benefit of treatment (10). In the
present study the drink at room temperature provided some
control for the study but direct comparisons between the two
data sets have not been made as it is not only the temperature
of the drink that provides the benefit of symptom relief. The
taste of the drink with both sweet and acidic components is
similar to traditional colds remedies such as honey and lemon,
and the stimulation of both sweet and acid gustatory receptors
provides a maximum stimulus for salivation and airway secre-
tions. The study drink had low sugar content, and traditional
colds remedies often use a high sugar content. It is possible
that even greater relief of colds symptoms, especially for cough
and sore throat could have been obtained with a drink with
higher sugar content (8).
82733_Sanu:and Eccles 12-11-2008 08:56 Pagina 274
Hot drink and common cold symptoms 275
CONCLUSIONS
The paradoxical sensation of improved airflow and a decrease
in nasal conductance observed in this study is still poorly
understood and does not appear to be due to a placebo effect.
The study demonstrates that a hot fruit drink can provide sub-
jective relief for common cold symptoms and that this effect
may be to due to both physiological and psychological effects
of the drink.
REFERENCES
1. Fokkens W, Lund V, Mullol J. European position paper on
rhinosinusitis and nasal polyps 2007. Rhinology. 2007: 1-136.
2. Martin JS, Tansy MF. Thermal stimulation of the oral mucosa and
nasal airway resistance. J Dental Res. 1977; 56: 1313-1322.
3. Saketkhoo K, Januszkiewicz A, Sackner MA. Effects of drinking
hot water, cold water, and chicken soup on nasal mucus velocity
and nasal airflow resistance. Chest. 1978; 74: 408-410.
4. Lal D, Gorges ML, Ungkhara G, Reidy PM, Corey JP.
Physiological change in nasal patency in response to changes in
posture, temperature, and humidity measured by acoustic rhinom-
etry. Am J Rhinol. 2006; 20: 456-462.
5. Clarke JD, Eccles R. Paradoxical sensation of nasal airflow in
patients with common cold. Are we measuring the correct modali-
ty? Acta Otolaryngol (Stockh). 2005; 125: 1307-1311.
6. Eccles R, Jawad MS, Jawad SS, Angello JT, Druce HM. Efficacy
and safety of single and multiple doses of pseudoephedrine in the
treatment of nasal congestion associated with common cold. Am J
Rhinol. 2005; 19: 25-31.
7. Evans D. Placebo. The belief effect. London: Harper Collins 2003.
8. Eccles R. Mechanisms of the placebo effect of sweet cough syrups.
Respir Physiol Neurobiol. 2006; 152: 340-348.
9. Naito K, Komori M, Kondo Y, Takeuchi M, Iwata S. The effect of
L-menthol stimulation of the major palatine nerve on subjective
and objective nasal patency. Auris Nasus Larynx. 1997; 24: 159-62.
10. Eccles R. The powerful placebo in cough studies. Pulm Pharmacol
Ther. 2002; 15: 303-308.
Professor Ron Eccles
Common Cold Centre and Healthcare
Clinical Trials
Cardiff School of Biosciences
Cardiff University
Cardiff CF10 3 US
United Kingdom
Tel: +44-(0)292-087 4102
Fax: +44-(0)292-087 4093
E-mail: eccles@cardiff.ac.uk
Editoiral
FELLOWSHIP JOURNAL RHINOLOGY – 2009
The journal ‘Rhinology’ is offering a Fellowship of € 10,000.-
during 2009 to enable a young researcher or clinician to visit
another academic department with an established reputation in
rhinology. The purpose of the visit is to observe or participate
in clinical or basic research. It is specifically not intended to
finance attendance at a meeting.
1. Candidates for “Rhinology” Travelling Fellowship should be
under 40 years of age and either a medically qualified
trainee or research worker in a University Department.
2. The Travelling Fellowships are tenable anywhere in the
world, preferably at a single medical centre with an estab-
lished interest in rhinology.
3. There is no period prescribed for the duration of a visit but
it is anticipated that Fellows will spend at least 4-6 weeks.
4. The Award will cover travel and assist with living expenses.
Any part of a grant which is unexpended must be returned
to the Rhinology Foundation.
5. Each Rhinology Travelling Fellow will be required to write
a report on his or her visit which should also include where
appropriate scientific work resulting from the Fellowship.
This must be offered to “Rhinology” within six months of
the return of the individual from the Fellowship.
6. A presentation based on the work undertaken during the
Fellowship will be given by the Fellow at the next ERS
meeting following the conclusion of their Fellowship.
7. Applications for the Awards for 2009 must reach the offices
of “Rhinology” before April 1st 2009 and must include the
following:
a) Curriculum Vitae.
b) An outline of the aims and objectives of the visit.
c) Letters of support from the applicant’s present consultant/
chief.
d) Letter of acceptance from the head of the department,
which they wish to visit.
e) An outline of expenses.
These should be sent to Mrs. Margot Wijnen, preferably by
e-mail (mwijnen@orange.nl) or by normal mail (4 copies) to:
Rhinology
P.O. Box 2233
3800 CE Amersfoort
THE NETHERLANDS
Fax No: 00-31-84-7304986
82733_Sanu:and Eccles 12-11-2008 08:56 Pagina 275
