Can menthol have harmful effects? What you need to know
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The bottom line
Menthol is the most abundant compound found in peppermint oil. Menthol can cause superficial irritation in small amounts and severe systemic symptoms in large amounts.
Prevention Tips
Natural products should be regarded to be potentially as dangerous as drugs.
Essential oils may be very concentrated and require dilution in a carrier oil to be used safely. Double check your products to make sure you are using them as directed.
Menthol gives the sensation of reducing congestion, but it actually can worsen congestion.
Menthol flavoring in cigarettes might be associated with a higher rate of addiction to smoking.
Smoking of all types of cigarettes, including mentholated cigarettes, is unhealthy.
Keep all menthol-containing products out of the reach and sight of children.
This Really Happened
Case 1. A mother called her poison center because an older child poured peppermint oil on her 3-month-old baby's head. She thought that it likely got into the baby's eyes and perhaps into his mouth as well. The baby was not opening his eyes, the skin looked irritated and red, and the baby was crying. The poison center recommended washing the baby's skin with soap and water, gently irrigating the eyes with water, and giving the baby something to drink, either by nursing or by giving formula.
About an hour later, the mother brought the baby to an ER because she was worried. The ER physician called a poison center to review the toxicity of peppermint oil and menthol. The physician reported that although the infant looked well, there was concern that some of the product might have been aspirated (leaked into the lungs). The poison center said that when aspiration is suspected, a chest x-ray should be done about 6 hours after the substance was swallowed. The x-ray was done, and it was normal. The skin irritation went away with no additional treatment beyond washing with soap and water.
Case 2. A 26-year-old woman suffered for 2 years from mild, scaly, red patches that would appear periodically on her upper lip, around her mouth, and on the tops of 2 of her fingers. She already knew that she had some chemical sensitivities because she was unable to handle any type of adhesive tape (she would get a red, itchy rash).
She was referred to a contact dermatitis specialist who did some skin patch testing and found that she was sensitive to some commonly found substances. She was given a long list of things to avoid. Her symptoms improved, but she would still have the breakouts.
The doctors performed a study with 100 patients, and the woman was the only one who reacted to 2 products that had 1 thing in common: they both contained menthol. She admitted that she regularly smoked menthol cigarettes but did not stick with a particular brand. She did not use any other products that contained menthol. She figured out which brand was causing the problem and stopped smoking that brand. She remained symptom-free after that (from Camarasa & Alomar, 1978).
What is menthol?
Essential oils are derived from plants. Their purpose is not exactly known, but some experts think that it could be a protective mechanism for the plant; others propose that they might attract pollinators. Peppermint is a popular essential oil used alone and in combination with other essential oils. Menthol is the main component of peppermint oil and is responsible for the noticeable cooling sensation. Menthol is extracted from plants or synthesized and can be found in throat lozenges, intranasal inhalers, lotions, pain creams, foods, and many other products.
How does menthol work?
Some people incorrectly believe that the cooling sensation from menthol is due to mechanical damage by menthol crystals or by evaporation (like when you touch rubbing alcohol), but this is not the case. Receptors that are responsible for feeling cold are triggered by menthol's effects on calcium and sodium channels, resulting in a cooling sensation. There are calcium and sodium channels in cell membranes throughout our bodies, which is why there can be systemic toxicity after swallowing or inhaling concentrated amounts of menthol. Serious effects include seizures, coma, and death.
Some nasal inhalers contain menthol. The menthol makes us feel as though we are breathing easier, but it does not actually help with congestion. In fact, it appears that more inflammation develops.
Skin and eye irritation
Menthol can cause eye and skin irritation. When used on the skin, menthol is typically diluted into a "carrier oil," lotion, or another vehicle, often in combination with other essential oils. If a high-percentage menthol product is applied to the skin, irritation and even chemical burns have been reported. There are a few reports of people being very sensitive to menthol and having severe skin reactions to even small amounts.
Is menthol flammable?
Products that contain menthol are potentially flammable. In 2000, the FDA added a warning against putting products with menthol near a flame, in hot water, or in a microwave oven. There is an additional warning about the dangers of applying a menthol product to the skin and placing a heating pad over it. The heat increases absorption through the skin. In one case, putting a heating pad on a menthol rub resulted in tissue death.
Menthol and smoking
Some researchers think that cigarettes with menthol might increase the risk of becoming addicted to smoking and might be more toxic than regular cigarettes. In a study of areas where menthol cigarettes have been banned such as Canada and the European Union, 24% of menthol cigarette smokers quit smoking after the ban. This suggests that their smoking was substantially in response to the menthol. Nicotine replacement products used to stop smoking work for menthol cigarette smokers as well.
Have more questions?
If you think someone might be having adverse effects or have taken too much menthol, use the webPOISONCONTROL® online tool to get help, or call your poison center at 1-800-222-1222. Whether online or by phone, expert guidance is always free, confidential, and available 24 hours a day.
For More Info
References
Camarasa G, Alomar A. Menthol dermatitis from cigarettes. Contact Dermatitis. 1978:4(3):169-170.
Eccles R. Menthol and related cooling compounds. J Pharm Pharmacol. 1994;46(6):618-630.
Noiles K, Pratt M. Contact dermatitis to Vicks VapoRub. Dermatitis. 2010;21(3):167-169.
Shawn LK. Essential oils. In: Nelson LS, Howland M, Lewin NA, Smith SW, Goldfrank LR, Hoffman RS. eds. Goldfrank's Toxicologic Emergencies. 11th ed. McGraw-Hill Education; 2019. Accessed July 19, 2025.
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