Peppermint is a hybrid. It is a cross between watermint and spearmint, and it is sterile, so it makes no seeds and spreads only by runners. A 2026 genome study of an elite peppermint clone calls it a sterile allohexaploid, a plant that carries six sets of chromosomes from its different parents. The mint in many grocery stores is actually spearmint, which has less menthol and a milder flavor.
The cool feeling is a trick of the nerves. Menthol, the main compound in peppermint oil, switches on cold-sensitive receptors called TRPM8 in the skin and mouth, so peppermint feels cold without being cold. The plant builds menthol in eight enzyme steps inside tiny oil glands on its leaves, and in lab work the leaves made oil only when they were 12 to 20 days old, with a peak at about 15 days.
Almost all the research below tested peppermint oil, often in capsules, and not the leaf or a cup of tea. The nutrition numbers on this page are for fresh leaves: 2 tbsp (3.2 g) has about 2 kcal and 0.3 g of fiber, and no vitamin or mineral reaches 5% of a day’s needs. One oddity is that our database has a measured amount of the flavanone eriodictyol in only 3 foods, and peppermint is one of them, at 0.99 mg per 2 tbsp.
Health benefits of peppermint
The top findings from 30 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Mixed results for irritable bowel symptomsAcross 12 trials (835 people), peppermint oil made overall improvement in irritable bowel syndrome 2.39 times as likely as placebo (risk ratio). Two other trials, one in 190 people, found no clear gain over placebo.
- ★★No clear help for belly pain in childrenIn 228 children with irritable bowel syndrome or belly pain, 44.0% improved on peppermint oil capsules and 37.3% on placebo. Peppermint sweets did no better than placebo either.
- ★★Calmed gut movement during endoscopyL-menthol, the main compound in peppermint oil, made gut movement stop far more often than placebo during endoscopy (odds ratio 6.51). It did not improve adenoma (polyp) detection, and this was the isolated compound, not the oil or leaf.
- ★Tea with a meal cut iron absorptionPeppermint tea drunk with a bread meal cut iron absorption by 84%. It tested iron that does not come from meat, so it matters most for people with low iron.
- ★Better scores on a thinking test after teaIn 25 adults, drinking 200 mL of peppermint tea improved scores on a computer test of thinking more than placebo. It was a single serving in a small trial.
All 30 studies, strongest evidence first
Peppermint oil was better than placebo for overall irritable bowel symptoms and belly pain in a 2022 meta-analysis, with more side effects
Meta-analysis of 10 randomized trials (1,030 people with irritable bowel syndrome) of peppermint oil, not leaf or tea. About 4 people needed treatment for one extra person to improve overall, and about 7 for belly pain. Side effects were more common with peppermint oil (relative risk 1.57), and the authors rated the quality of the evidence as very low.
Peppermint oil raised the chance of overall improvement in irritable bowel syndrome (risk ratio 2.39) compared with placebo
Meta-analysis of 12 randomized trials (835 people) of peppermint oil. For belly pain the risk ratio was 1.78. Side effects did not differ significantly from placebo (9.3% with peppermint oil and 6.1% with placebo).
Enteric-coated peppermint oil capsules improved overall irritable bowel symptoms (risk ratio 2.23) and belly pain (2.14) more than placebo
Meta-analysis of 9 randomized placebo-controlled trials (726 people) of enteric-coated peppermint oil capsules taken for at least 2 weeks. Side effects were more common with peppermint oil but mild and short-lived. Heartburn was the most common one.
In a comparison of older irritable bowel treatments, peppermint oil capsules ranked first for improving overall symptoms
Network meta-analysis of 51 randomized trials (4,644 people) of fiber, antispasmodic drugs, peppermint oil capsules and gut-brain drugs, lasting 4 to 12 weeks. Peppermint oil had a risk ratio of 0.63 for not improving. Only 13 trials had a low risk of bias, so the authors say the result is uncertain.
Peppermint oil capsules for 8 weeks did not beat placebo on the main measure of belly pain relief (46.8% responded against 34.4%) in irritable bowel syndrome
Double-blind trial in 190 people at 4 Dutch hospitals, comparing 182 mg of small-intestine-release peppermint oil, 182 mg of ileocolonic-release oil and placebo. Secondary measures of pain, discomfort and severity did improve more with the small-intestine-release oil, but mild side effects were more common with both oils.
Enteric-coated peppermint oil for 6 weeks did no better than placebo for moderate to severe irritable bowel syndrome
Double-blind trial at one US center comparing 180 mg of peppermint oil 3 times a day with placebo. Symptom scores improved by 90.8 points on peppermint oil and 100.3 on placebo. Both groups got clearly better, and the gap was not significant.
Peppermint oil capsules for 8 weeks did not beat placebo for belly pain in children with irritable bowel syndrome or functional abdominal pain (44.0% improved against 37.3%)
Randomized trial in 228 children aged 8 to 18 at 13 Dutch hospitals. Capsules held 182 mg of peppermint oil. Open-label peppermint sweets (9.2 mg of oil) did no better than placebo either (38.7%). Side effects were mild and infrequent.
L-menthol, the main compound of peppermint oil, made gut movement stop far more often during endoscopy (odds ratio 6.51) than placebo
Meta-analysis of 8 randomized trials (1,366 people) of L-menthol given during gastrointestinal endoscopy. It did not improve the adenoma detection rate (odds ratio 1.03), and side effects did not differ significantly from placebo. This is the isolated compound, not the oil or the leaf.
Drinking 200 mL of peppermint tea improved scores on a computer test of thinking more than placebo in 25 adults
Single-blind randomized trial that measured thinking with a computer battery and blood flow in the brain with near-infrared light, before and after the drink. Blood flow rose more after peppermint tea too, but it did not explain the thinking change. The group was small and the drink was a single serving.
Peppermint tea with a meal cut iron absorption from bread by 84%
Controlled test in adult volunteers who ate a bread meal with water or a test drink, using radioactive iron to track absorption. Black tea cut absorption by 79 to 94%, and other herb teas also lowered it. It tested iron that does not come from meat, so it matters most for people with low iron.
Enteric-coated peppermint oil capsules for 4 weeks cut irritable bowel symptom scores by more than half in 75% of people against 38% on placebo
Double-blind trial in 57 people in whom bacterial overgrowth, lactose intolerance and celiac disease had been ruled out. The dose was two capsules twice a day. Symptoms were still lower 4 weeks after treatment stopped, though not as low as during it.
Peppermint oil capsules for 8 weeks left 14 people free of belly pain or discomfort, against 6 on placebo
Double-blind trial in 90 outpatients with irritable bowel syndrome who took one enteric-coated, delayed-release capsule 3 times a day. Pain severity and quality of life also improved more than with placebo, and no significant side effects were reported.
Enteric-coated peppermint oil capsules for a month eased belly pain in 79% of people, against 43% on placebo
Double-blind trial in 110 outpatients with irritable bowel syndrome, with 52 on peppermint oil and 49 on placebo finishing. People took 1 capsule 3 to 4 times a day before meals. One person had heartburn from chewing the capsules and one had a mild rash.
Enteric-coated peppermint oil capsules for 2 weeks reduced pain severity in 75% of children with irritable bowel syndrome
Double-blind trial in 42 children. The abstract does not give the placebo result. A much larger 2026 trial in children, above, found no benefit over placebo.
A peppermint and caraway oil capsule for 4 weeks relieved indigestion pain more than placebo (7.6 against 3.4 points)
Double-blind trial in 114 outpatients with functional dyspepsia, who took one capsule of a fixed peppermint and caraway oil product twice a day. Peppermint oil alone was not tested, so the result cannot be credited to peppermint by itself.
Peppermint oil capsules taken 4 hours before colonoscopy lowered colon spasm and pain scores and shortened the procedure
Double-blind trial in 65 adults, 33 given enteric-coated capsules and 32 given placebo. Patients on peppermint oil were also more willing to repeat the test, and the endoscopist was more satisfied.
Peppermint oil capsules taken 4 hours before colonoscopy did not shorten the time to reach the cecum compared with placebo
Double-blind trial in 80 patients. Patient tolerance, endoscopist satisfaction and the need for sedation did not change either, and the authors do not support routine use before colonoscopy.
A sustained-release peppermint oil product before colonoscopy did not reduce colon spasm or raise polyp detection (47.8% against 43.1%)
Double-blind trial at one center in people having screening or surveillance colonoscopy. Spasm scores matched in the two groups (1.23 against 1.2 on insertion). The authors say a well-timed formulation still deserves study.
Peppermint oil solution put into the stomach through the endoscope stopped stomach spasm faster than an injected muscle relaxant (97.1 against 185.9 seconds)
Double-blind, double-dummy trial in 100 patients having upper endoscopy, comparing the oil with an injection of hyoscine-N-butylbromide. The oil had no significant side effects, while the injection caused dry mouth, blurred vision and urinary retention.
A 10% peppermint oil solution rubbed on the forehead and temples eased tension headache about as well as 1,000 mg of acetaminophen
Double-blind crossover trial in 41 people treating 164 headache attacks, with the oil on the skin repeated at 15 and 30 minutes. Pain was lower than with placebo within 15 minutes and stayed lower for the hour of observation. No side effects were reported. This oil is applied to the skin, not eaten.
Peppermint extract capsules taken for 3 days of a period lowered period pain and how long it lasted in students with painful periods
Double-blind crossover trial in 127 students, comparing peppermint capsules with mefenamic acid, a painkiller. Bleeding was lower and less pain medicine was used with mefenamic acid, while nausea and diarrhea were lower with peppermint.
In a Cochrane review, inhaling peppermint did not clearly lessen nausea after surgery compared with placebo
Review of 16 aromatherapy trials (1,036 people) for nausea after surgery. For peppermint against placebo the pooled result was small and uncertain (4 trials, 115 people), and the evidence was rated low quality. Peppermint was inhaled, not swallowed.
One drop of peppermint oil under the nose 3 times a day lowered nausea scores in most chemotherapy regimens but not with cisplatin
Quasi-randomized study in cancer patients in Turkey, with the oil used for 5 days after chemotherapy on top of the usual anti-nausea drugs. It was not fully randomized, and the abstract gives no group sizes. The oil was smelled, not swallowed.
Inhaling peppermint oil for four days did not ease morning sickness more than placebo in 56 pregnant women
Single-blind trial in women at 6 to 20 weeks of pregnancy with mild to moderate nausea and vomiting. Symptoms fell in both groups, and the authors suggest the effect may be psychological.
The scent of peppermint improved memory and raised alertness in 144 volunteers
Volunteers were randomly assigned to peppermint aroma, ylang-ylang aroma or no aroma and then did a computerized test battery. This tested a smell, not food or drink.
A 100 µL dose of peppermint oil in a capsule improved performance on a demanding attention task and eased mental fatigue
Double-blind crossover trial in 24 healthy adults (mean age 25) who took placebo, 50 µL or 100 µL once, with tests at 1, 3 and 6 hours. The higher dose helped at 1 and 3 hours, and both doses reduced fatigue at 3 hours. It was a single dose in young adults.
Menthol put into the esophagus did not change the pressure of the lower esophageal sphincter in healthy people or in people with reflux
Pressure-measurement study with menthol infused through a tube in 13 healthy people and 11 with gastroesophageal reflux disease. People with reflux felt more discomfort than healthy people. Menthol is the main compound of peppermint oil, and the authors suggest other mechanisms cause menthol-related heartburn.
Rats drinking peppermint tea (20 g per liter) had lower testosterone and higher FSH and LH than rats drinking water
Experimental study in 48 male rats, 12 per group, given peppermint tea, spearmint tea at two strengths, or water. Peppermint caused only partial arrest of sperm maturation in some tubules, and spearmint caused more. Rat results do not show the same happens in people.
Peppermint oil and menthol blocked calcium channels in gut muscle from guinea pigs, which may explain the cramp relief
Lab tests on guinea-pig intestine, heart muscle from rats and guinea pigs, and nerve preparations. Menthol was about twice as potent as peppermint oil. The authors note that calcium blocking may not be the only way the oil relaxes gut muscle.
Menthol, the main compound of peppermint oil, reduced contractions of human colon muscle in a lab dish by blocking calcium channels
Lab study on circular muscle strips from the human colon, using menthol from 0.1 to 30 mM. It lowered the strength of contractions without changing their frequency or the resting tone of the muscle.
Who should be careful with peppermint
Most people can eat peppermint freely, and the NIH says peppermint tea appears safe. Take a little care if one of these applies:
- Heartburn and reflux. Heartburn was the most common side effect of peppermint oil capsules in trials, and the NIH says enteric coating is used to lessen it. A pressure test found menthol did not change the lower esophageal sphincter, so why it happens is unclear, and no study here tested peppermint tea for reflux.
- Babies and young children. The NIH says menthol should not be breathed in or put on the face of an infant or small child because it can affect their breathing. EU regulators also advise against peppermint oil medicines taken by mouth for belly complaints under age 8.
- Gallstones, liver disease or low stomach acid. EU regulators say peppermint oil medicines for minor belly problems must not be used with these conditions or with other bile-related problems. This is about oil medicines, not tea.
How to choose, store and eat peppermint
- Fresh leaves: a 2 tbsp (3.2 g) serving has about 2 kcal, so they add flavor to tea, drinks, fruit salad, lamb or potatoes rather than nutrition.
- Tea: the NIH says peppermint tea appears safe, though the long-term safety of large amounts is unknown. Peppermint tea cut iron absorption from a bread meal by 84% in one test, so people with low iron may prefer it between meals.
- Oil capsules: the irritable bowel trials used enteric-coated capsules of 180 to 182 mg, taken 2 to 3 times a day for 6 to 8 weeks. They are sold as supplements or medicines, so ask a pharmacist first if you take other medicines.
Look for vibrant green leaves and avoid brown or wilted ones. Wrap fresh mint in a moist paper towel, put it in a zip-top bag and keep it in the refrigerator, where it lasts several days, or freeze or dry it for longer. Mint sold in grocery stores is often spearmint, so check the label if you want peppermint.
Sources
- Peppermint oil: usefulness and safety. National Center for Complementary and Integrative Health, NIH. Updated May 2025.
- Menthae piperitae aetheroleum (peppermint oil): herbal medicinal product. European Medicines Agency, summary of the HMPC conclusions. 2020.
- Mint. FoodLink, Purdue Extension.
- Khanna R, MacDonald JK, Levesque BG. Peppermint oil for the treatment of irritable bowel syndrome: a systematic review and meta-analysis. J Clin Gastroenterol. 2014.
- Nee J, Ballou S, Kelley JM, et al. Peppermint oil treatment for irritable bowel syndrome: a randomized placebo-controlled trial. Am J Gastroenterol. 2021.
- Weerts ZZRM, Masclee AAM, Witteman BJM, et al. Efficacy and safety of peppermint oil in a randomized, double-blind trial of patients with irritable bowel syndrome. Gastroenterology. 2020.
- Liu JH, Chen GH, Yeh HZ, Huang CK, Poon SK. Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: a prospective, randomized trial. J Gastroenterol. 1997.
- Bánovčin P, Lipták P, Vážanová D, et al. Esophageal infusion of menthol does not affect esophageal motility in patients with gastroesophageal reflux disease. Dysphagia. 2024.
- Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. Br J Nutr. 1999.
History of peppermint
Peppermint is a newcomer among herbs. The NIH says mint plants have been used for digestive complaints since ancient Greece, Rome and Egypt, but peppermint itself was first written down in 1696. The English naturalist John Ray published a mint that a Dr. Eales had found in Hertfordshire, and in 1704 Ray called it Peper-Mint.
The London Pharmacopoeia listed peppermint in 1721, and Carl Linnaeus gave it the name Mentha piperita in 1753. Linnaeus treated it as a species. Botanists now agree it is a hybrid of watermint and spearmint.
Mitcham, near London, was an herb-growing district where peppermint and lavender oils were distilled. In 1749 two local herb growers, John Potter and William Moore, founded a company there to make toiletries from locally grown herbs and flowers. Cultivars with Mitcham in their names are still grown today.
Peppermint also escaped. Where it was once grown for oil it often turned up wild, and it is now considered invasive in Australia, the Galápagos Islands, New Zealand and the Great Lakes region of the United States, where it has been noted since 1843.
Disease shaped the crop. Verticillium wilt is a major problem for growers, and from the mid-1950s the Brookhaven National Laboratory used radiation breeding to produce ‘Todd’s Mitcham’, a cultivar that resists it.
Most peppermint oil now goes into flavorings. In 2020 Oregon and Washington produced most American peppermint, which is processed mainly for chewing gum and toothpaste. World production in 2023 was 35,547 metric tons, with 78% from Morocco and 20% from Argentina.
Sources
- Peppermint. Wikipedia.
- Mitcham. Wikipedia.
- Peppermint oil: usefulness and safety. National Center for Complementary and Integrative Health, NIH. Updated May 2025.
- Mint. FoodLink, Purdue Extension.
- Kippes N, Lieberman MC, Culp D, et al. Layer-specific genetic variation unlocks secondary metabolite diversity in long-lived clonal peppermint. Proc Natl Acad Sci U S A. 2026.
- Croteau RB, Davis EM, Ringer KL, Wildung MR. (-)-Menthol biosynthesis and molecular genetics. Naturwissenschaften. 2005.
- McConkey ME, Gershenzon J, Croteau RB. Developmental regulation of monoterpene biosynthesis in the glandular trichomes of peppermint. Plant Physiol. 2000.
- Ray J. Synopsis Methodica Stirpium Britannicarum, 2nd ed. 1696 (as cited by Wikipedia).
Frequently asked questions about peppermint
Is peppermint good for you?
In small amounts it is safe, but it is a flavor, not a source of nutrients. Fresh peppermint has about 2 kcal and 0.3 g of fiber in 2 tbsp (3.2 g), and no vitamin or mineral reaches 5% of a day’s needs. The best-supported benefit is for irritable bowel symptoms, from peppermint oil capsules rather than the leaf, and even that evidence is rated low in quality.
Does peppermint oil help irritable bowel syndrome?
It may, but the evidence is mixed. A 2022 meta-analysis of 10 trials (1,030 people) found peppermint oil better than placebo, with about 4 people treated for one extra person to improve overall, though side effects were more common and the quality was very low. Then an 8-week trial in 190 people missed its main pain goal (46.8% responded against 34.4% on placebo), and a 6-week US trial found no difference at all.
Is peppermint tea good for you?
Peppermint tea appears safe, but little about it is proven. The NIH says long-term safety of large amounts is unknown. One small trial found that 200 mL improved a computer test of thinking in 25 adults, and one test found it cut iron absorption from a bread meal by 84%. No trial here shows that tea eases digestion the way the capsules might.
Does peppermint help with nausea?
The evidence is weak. In a Cochrane review, inhaled peppermint did not clearly lessen nausea after surgery (4 trials, 115 people), and in 56 pregnant women it did no better than placebo over four days. One chemotherapy study found lower nausea scores with a drop of oil under the nose, but it was not fully randomized. None of these tested tea.
Does peppermint cause heartburn?
Peppermint oil capsules can. Heartburn was the most common side effect in a meta-analysis of 9 trials, and the NIH lists it too. In a pressure test in 13 healthy people and 11 with reflux disease, menthol did not change the lower esophageal sphincter, so the cause is unclear. No study here tested tea for reflux, so if tea gives you heartburn, drink less of it.
Is peppermint the same as spearmint?
No. Peppermint is a hybrid of watermint and spearmint, and it has more menthol, so its flavor is more intense. Mint sold in grocery stores is often spearmint. The studies on this page are on peppermint, and results for spearmint cannot be assumed to match.
How many calories are in peppermint?
Almost none. Fresh peppermint has about 2 kcal in 2 tbsp (3.2 g), along with 0.3 g of fiber and 0.1 g of protein. Because it is eaten in such small amounts, it adds flavor and not nutrition.
Is peppermint safe for babies and children?
Not on or near the face. The NIH says menthol should not be breathed in or put on the face of an infant or small child, and EU regulators advise against peppermint oil medicines taken by mouth for belly complaints under age 8. A 2026 trial in 228 children aged 8 to 18 found mild and infrequent side effects but no benefit over placebo.