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Menthol is a monocyclic terpene alcohol, which is present naturally in peppermint and can be synthesized artificially as well. Generally, it is considered as very safe and has wide usage in medicine and food. There are case reports of toxicity due to excessive consumption of menthol, but a fatal intoxication has never been reported in the medical literature. We present a case of fatal menthol intoxication in a worker, who accidently got exposed when he was working in a peppermint factory. Emergency physicians must keep in mind this extremely rare manifestation of menthol poisoning. All necessary precaution should be taken to reduce its intake or exposure, as it has no specific antidote. Early recognition and supportive treatment of this poisoning is the key for a successful outcome.
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© 2016 International Journal of Applied and Basic Medical Research | Published by Wolters Kluwer - Medknow 137
A fatal case of menthol poisoning
Akshay Kumar, Upendra Baitha, Praveen Aggarwal, Nayer Jamshed
Department of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India
A
Menthol is a monocyclic terpene alcohol, which is present naturally in peppermint and can be synthesized articially as well.
Generally, it is considered as very safe and has wide usage in medicine and food. There are case reports of toxicity due to
excessive consumption of menthol, but a fatal intoxication has never been reported in the medical literature. We present a
case of fatal menthol intoxication in a worker, who accidently got exposed when he was working in a peppermint factory.
Emergency physicians must keep in mind this extremely rare manifestation of menthol poisoning. All necessary precaution
should be taken to reduce its intake or exposure, as it has no specic antidote. Early recognition and supportive treatment
of this poisoning is the key for a successful outcome.
Key words: Hematuria, menthol, peppermint, renal dysfunction, seizure
Submission: 01‑06‑2015 Accepted: 22‑11‑2015
Address for correspondence: Dr. Nayer Jamshed,
Department of Emergency Medicine, All India Institute of
Medical Sciences, Aurobindo Marg, New Delhi ‑ 110 029, India.
E‑mail: jamshednayer@gmail.com
I
Menthol is a monocyclic terpene alcohol having 3
asymmetric carbon atoms in the cyclo‑hexane ring.
Naturally, it is present in peppermint but can also be
obtained synthetically. It is widely used as cooking oils,
candies, mouth fresheners, cigarette, and desserts. It
has also been effectively used as herbal and alternative
medicine in common cold, flu, and as a digestive aid. It has
a cooling, analgesic, and muscle‑relaxing effect through
transient receptor potential cation channel subfamily
M member 8, kappa, and voltage‑gated sodium channel
receptors, respectively.[1] Menthol is generally considered
safe and its toxic effect has rarely been reported in the
literature. We here report for the 1st time a case of fatal
menthol toxicity after acute exposure.
C R
A twenty‑one‑year‑old farmer living in a village of Uttar
Pradesh, India, was brought to our emergency department
in unconscious state. The history suggested that 4 days ago,
he was asked to clean a tank in a peppermint factory. He
got down inside the tank and soon after the inhalation of
toxic fumes, he was found in unconscious state. It took
an hour to bring him out from the tank. He remained
unconscious and then developed recurrent convulsions
and intermittent hematuria. The recurrent seizure activity
was controlled with intravenous midazolam followed by
intravenous levetiracetam. Supportive treatment such
as nasogastric lavage and intravenous uids were also
given. The patient was then referred to our Tertiary Care
Center, where we received the patient in the emergency
department with stable vitals, pulse 90/min, blood pressure
130/70 mm of Hg, respiratory rate 16/min, and Glasgow
coma scale (GCS) of E3V2M3. On the further history and
clinical examination, there was no upper or lower limb
weakness, or myoclonic jerks. Pupils were normal in size
Case Report
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DOI:
10.4103/2229-516X.179015 How to cite this article: Kumar A, Baitha U, Aggarwal P, Jamshed N. A
fatal case of menthol poisoning. Int J App Basic Med Res 2016;6:137-9.
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Kumar, et al.: Fatal menthol poisoning
International Journal of Applied and Basic Medical Research, Apr-Jun 2016, Vol 6, Issue 2
138
and were reactive to light, and there was no neck rigidity. The
patient had an increased muscle tone in all 4 limbs, and the
deep tendon reexes were exaggerated. There was no history
of substance abuse, smoking, alcohol intake, and medications.
The patient’s past medical history was also noncontributory.
His blood results showed hemoglobin 13.1 g/L, total leukocyte
count 10,400/µL, platelet 180,000/µL, blood urea 44 mg/dL,
serum creatinine 2.8 mg/dL, Na 146 mEq/L, K 3.9 mEq/L, blood
sugar 119 mg/dL, serum glutamic oxaloacetic transaminase
148 U/L, serum glutamic pyruvic transaminase 86U/L,
and bilirubin 1.1 mg/dL. Chest radiograph [Figure 1] and
electrocardiogram [Figure 2], cerebrospinal uid examination
were within normal limits. Urine microscopy showed several
red blood cells/high power eld. Urine culture was sterile.
Urine toxicology screen was positive for benzodiazepine,
probably secondary to intravenous midazolam, which was
given to control the seizures. His arterial blood gas showed
pH 7.49, PaO2 68 mmHg, PCO2 59.1 mmHg, and HCO3 30
mEq/L with carboxyhemoglobin level of 1.4%. Noncontrast
computed tomography brain showed loss of gray‑white matter
differentiation and evidence of cerebral edema [Figure 3].
The patient remained in a coma due to low GCS patient
was intubated to protect his airways. He was continued on
levetiracetam, but sodium valproate and midazolam infusion
was added to control the seizures. The patient remained
unconscious with poorly controlled recurrent seizures.
During his hospital stay, he developed ventilator associated
pneumonia, sepsis with shock, and acute renal dysfunction.
Broad spectrum antibiotics, intravenous uids, nor‑adrenaline,
and dopamine were added along with other supportive
measures. Unfortunately, the patient expired after 10 days
of hospitalization.
D
Peppermint oil is a herbal extract from essential oils
of peppermint leaves, which is widely grown in the
state of Uttar Pradesh in India. Menthol is the principal
ingredient of peppermint. The United States Food and Drug
Administration and the Flavoring Extract Manufacturer’s
Association generally consider menthol, a safe substance
and its toxicities are rarely been reported in the
literature. Ingestion of pure menthol can be dangerous
and its over dosage is possible with excess consumption
of menthol‑containing products. Orally, the lethal dose
has been estimated as 50–150 mg/kg.[2] Several adverse
effects of peppermint oil have been reported that include
dermatitis, cheilitis, mouth ulceration, abdominal pain,
nausea, vomiting, bradycardia, and tremor. Chronic exposure
to menthol ingestion has been reported in the USA and is
associated with cutaneous, gastrointestinal, and neurological
manifestations.[3] A high dose of peppermint oil ingestion
was also reported where the patient presented in transient
shock, hematuria, renal, and respiratory failure.[4] Renal
dysfunction is common probably because of interstitial
nephritis. An excessive amount of menthol is also reported
to have caused agitation, dizziness, ataxia, hallucination,
convulsion, and coma.[5] There is no specific antidote
Figure 1: Normal chest radiograph of the patient
Figure 2: Normal 12 lead electrocardiograph of the patient
Figure 3: Noncontrast computed tomography brain showed loss of gray-white
matter differentiation and evidence of cerebral edema
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Kumar, et al.: Fatal menthol poisoning
International Journal of Applied and Basic Medical Research, Apr-Jun 2016, Vol 6, Issue 2 139
available for menthol poisoning. The management includes
gastrointestinal decontamination, oral activated charcoal
along with other supportive measures. Complications
such as seizure, respiratory failure, renal dysfunction, and
shock should be managed accordingly. Prognosis in menthol
poisoning depends on the dose of ingestion, duration
of exposure, and how quickly the medical treatment is
provided to the patient.
Above, we presented a rare case of hypoxic brain injury,
hematuria, and acute renal failure secondary to recurrent
seizure activity after acute and heavy exposure to menthol,
which ultimately proved fatal.
C
Menthol is widely used and is considered very safe.
Prolonged and heavy exposure of menthol can cause severe
intoxication and even death. All necessary precaution should
be taken to reduce its intake or exposure. Early recognition
and treatment of this poisoning is key for the successful
outcome.
Financial support and sponsorship
Nil.
Conicts of interest
There are no conicts of interest.
R
1. Gaudioso C, Hao J, Martin‑Eauclaire MF, Gabriac M, Delmas P. Menthol
pain relief through cumulative inactivation of voltage‑gated sodium
channels. Pain 2012;153:473‑84.
2. Gosselin RE, Hodge HC, Smith RP, Gleason MN. Clinical Toxicology of
Commercial Products. 4th ed. Baltimore: Williams and Wilkins; 1976.
p. II‑168.
3. Baibars M, Eng S, Shaheen K, Alraiyes AH, Alraies MC. Menthol toxicity:
An unusual cause of coma. Case Rep Med 2012;2012:187039.
4. Nath SS, Pandey C, Roy D. A near fatal case of high dose peppermint
oil ingestion‑lessons learnt. Indian J Anaesth 2012;56:582‑4.
5. Opdyke DL. Monographs on fragrance raw materials. Food Cosmet
Toxicol 1976;14:307‑38.
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... Menthol is generally considered a safe substance and is widely used by the food, drug, and cosmetic industry, yet cases of toxicity due to the ingestion of high doses have been reported in scientific literature (Kumar et al., 2016). The lethal oral dose of menthol is between 50 and 150 mg/kg, and adverse events due to overdose include respiratory and kidney failure along with neurological, cutaneous, and gastrointestinal manifestations (Kumar et al., 2016). ...
... Menthol is generally considered a safe substance and is widely used by the food, drug, and cosmetic industry, yet cases of toxicity due to the ingestion of high doses have been reported in scientific literature (Kumar et al., 2016). The lethal oral dose of menthol is between 50 and 150 mg/kg, and adverse events due to overdose include respiratory and kidney failure along with neurological, cutaneous, and gastrointestinal manifestations (Kumar et al., 2016). Therefore, prolonged and heavy exposure to menthol is to be avoided. ...
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Clinical Toxicology of Commercial Products. 4 th ed. Baltimore: Williams and Wilkins
  • R E Gosselin
  • H C Hodge
  • R P Smith
  • M N Gleason
Gosselin RE, Hodge HC, Smith RP, Gleason MN. Clinical Toxicology of Commercial Products. 4 th ed. Baltimore: Williams and Wilkins; 1976. p. II-168.
Baltimore: Williams and Wilkins
  • R E Gosselin
  • H C Hodge
  • R P Smith
  • M N Gleason