Peppermint

Mentha × piperita · Lamiaceae · leaf and flowering tops

Also known as brandy mint, lamb mint. Related to Bo He (Chinese medicine, a different mint species) and pudina (Hindi)

Pungent
Aromatic
Cooling then warming
Drying
Carminative
Antispasmodic
Diaphoretic
Diffusive

Educational content, not medical advice. I am a certified clinical herbalist, not a physician. Nothing on this page diagnoses, treats, or cures any condition, and none of it replaces care from your own healthcare provider. Do not stop or change a prescribed medication based on anything you read here. Peppermint tea and peppermint oil are different substances at different strengths, and the oil in particular can interact with medications and health conditions, so talk with your doctor or pharmacist before using peppermint beyond food amounts.

About Peppermint

Peppermint is a perennial in the mint family, Lamiaceae, with square stems, dark toothed leaves, and small purple flowers in whorls. It is a natural cross between water mint (Mentha aquatica) and spearmint (Mentha spicata), which is why botanists write the name with a multiplication sign. Hybrids rarely set viable seed, so peppermint spreads by runners and is propagated from cuttings.^1,20

Native range: King's American Dispensatory records peppermint as "indigenous to England," where it was first recognized as distinct from other mints around 1700, then carried through Europe and North America.^1,20
Where it grows now: damp ground in temperate regions worldwide. Commercial oil distillation in the United States began in Wayne County, New York, in 1816 and moved to Michigan by 1835; the Pacific Northwest now leads American production.¹
Two cultivated forms: black mint, with purple-tinged stems and higher oil yield, and white mint, with green stems and a more delicate scent, which Grieve says was the form dried for herbalists.³
Identifying the dried leaf: the U.S. Pharmacopoeia description quoted in King's: leaves about 2 inches long, sharply toothed, nearly smooth, with a few hairs that hold crystals of menthol; odor aromatic; taste pungent and cooling.¹
Harvest: King's advises collecting the whole herb as the flowers begin to open and drying it in shade, and notes the fresh plant is stronger than the dried.¹
Growing conditions: moist soil, sun to part shade, and a container or barrier, because the runners will take a bed. It survives Zone 5 winters without protection.

Peppermint, spearmint, and Bo He

Spearmint is one of peppermint's two parents and carries carvone rather than menthol, so it tastes sweeter and does not produce the cold sensation. Bo He, the mint of the Chinese materia medica, is Mentha haplocalyx, now generally treated as the same species as Japanese mint, Mentha canadensis. It is menthol-rich like peppermint and is used differently, as covered under Traditional Use. When a source on this page says peppermint, it means the hybrid Mentha × piperita unless stated otherwise.

Traditional Use

The traditions below describe how practitioners have used peppermint. These are historical and clinical records, not instructions. None of this is medical advice.

Energetics

Peppermint is pungent and aromatic. The first sensation is cold, because menthol acts on the same nerve receptors that register cool temperatures. A warming, stimulating effect follows. King's described the taste in 1898 as "warm, burning, bitter," followed by "a feeling of coolness during inhalation."¹ Both readings are correct, and the order matters when matching the herb to a person.

Western herbalism: a diffusive stimulant that moves outward, drying to excess moisture, relaxing to cramped muscle.^1,2
Ayurveda: Sebastian Pole classifies mint as cooling and pungent, reducing pitta (heat) and kapha (heaviness), and able to increase vata (dryness, restlessness) in large amounts.⁹
Chinese medicine: Bensky lists Bo He as acrid and cool, entering the Lung and Liver channels, used to disperse wind-heat from the head, throat, eyes, and skin and to move constrained Liver qi.¹⁰

It suits people who run warm and hold tension in the gut. It is a poor match for someone who is chronically cold, dry, and depleted. Ellingwood advised against it when the abdomen is tender to pressure and the tongue is dry with a red tip, signs he read as active inflammation rather than the atonic (sluggish) state peppermint fits.²

The Eclectics

King's American Dispensatory (1898) calls peppermint "a powerful diffusive stimulant, antispasmodic, carminative, stomachic, and weak anodyne" with "marked antiseptic properties." In plain terms, it spreads warmth quickly, relaxes cramping muscle, relieves gas, supports the stomach, and dulls minor pain. The Eclectics used it for:¹

gastrodynia (stomach pain), flatulent colic, and spasms or cramps of the stomach, which King's names as its specific indications along with "difficult digestion"
nausea and vomiting
the griping caused by strong laxatives
covering the taste of other medicines
the cough of bronchitis and pneumonia, as equal parts essence and alcohol sprayed by atomizer
the fresh herb, bruised and laid over the bowels, for "sick stomach" and infant diarrhea, and on the forehead for headache

Ellingwood (1919) added the warm infusion to raise a sweat at the start of a feverish cold and used the oil locally to relieve itching and the pain of burns and carious teeth.²

British herbalism

Maud Grieve's A Modern Herbal (1931) gives peppermint for "spasms of wind, colic, and diarrhoea" and pairs it with elder flower for the early stage of a cold. She insists the infusion be made and kept in a covered vessel so the steam, and the oil with it, cannot escape.³

Chinese medicine: Bo He

Bo He is used for a different purpose than Western peppermint. Bensky records it for wind-heat patterns: fever with headache, red eyes, sore throat, and early rashes, and for Liver qi constriction with chest and flank tension. It is added in the last minutes of a decoction so the volatile oil survives. His contraindications are exterior deficiency with spontaneous sweating and yin deficiency with heat signs.¹⁰

European regulatory monographs

Germany's Commission E approved peppermint leaf for spastic complaints of the digestive tract, gallbladder, and bile ducts, and peppermint oil for the same internally plus tension headache and respiratory catarrh externally.⁴ The European Medicines Agency's 2020 leaf monograph accepts the dried leaf as a traditional product "for the symptomatic relief of digestive disorders such as dyspepsia and flatulence."⁵ Its 2020 oil monograph goes further and grants "well-established use," the EMA's higher evidence tier, to enteric-coated peppermint oil for spasms, flatulence, and abdominal pain in irritable bowel syndrome, and to 10 percent oil in ethanol on the temples for mild tension headache.⁶ Health Canada accepts "traditionally used to help relieve flatulent dyspepsia" as a lawful label claim.⁷

Modern clinical use

David Hoffmann lists peppermint as carminative, antispasmodic, aromatic, diaphoretic, antiemetic, and nervine, and uses it in nausea, colic, and tension headache.⁸ Contemporary herbalists also apply the cooled infusion or diluted oil to itchy, hot skin. If digestion is your interest, my gut health articles cover how peppermint fits alongside other carminatives, and ginger is its warming counterpart for nausea in cold constitutions.

Constituents and What They Do

Peppermint's chemistry splits into two groups that dissolve in different things. That split decides how you prepare it, which the preparations section builds on.

Constituent	Amount and solubility	What studies show
Volatile oil: menthol, menthone, menthyl acetate, 1,8-cineole, and minor terpenes	1 to 3 percent of the dried leaf. Menthol is 30 to 55 percent of the oil and menthone 14 to 32 percent under the European Pharmacopoeia standard.⁶ Dissolves in alcohol and fat, poorly in water, and evaporates with steam.¹	Menthol activates the cold-sensing receptor TRPM8 on nerve endings, which is the cooling feeling. In isolated gut muscle it relaxes smooth muscle by blocking calcium entry into the cells (laboratory tissue work), the mechanism behind the IBS, headache, and drug-interaction research below.¹⁷ The EMA describes the oil as antispasmodic, bile-promoting, and antifoaming in the gut.⁶
Pulegone and menthofuran (part of the volatile oil)	1 to 11 percent of the oil combined; the Pharmacopoeia caps pulegone at 4 percent.⁶ Fat and alcohol soluble.	The safety-limiting compounds. In rats and mice at high doses they caused liver and urinary tract tumors through sustained cell damage, not through genetic damage. The EMA sets a daily ceiling of 37.5 mg for adults and 0.75 mg per kg for children.⁶ Animal data at doses far above tea; relevant to concentrated oil products.
Rosmarinic acid and related phenolic acids (caffeic, chlorogenic)	Water and alcohol soluble.	Antioxidant and anti-inflammatory activity in laboratory work. No human trial has tested peppermint leaf for these effects.
Flavonoids: eriocitrin, luteolin, apigenin, hesperidin	Water and alcohol soluble. Eriocitrin is a leaf quality marker in some pharmacopoeias.	Antioxidant activity in the lab. No peppermint-specific human outcome data.
Tannins	Water soluble. King's identified them in 1898 because the infusion turns dark green with iron salts.¹	Mild astringency. Tannins can reduce iron absorption when tea is taken with meals, which Health Canada notes under cautions.⁷

What the Research Shows

Almost every good trial used the concentrated oil in capsules, not the leaf. Pooled together, those trials show enteric-coated oil beats placebo for irritable bowel symptoms and pain, with heartburn as the trade-off and a low certainty rating from the reviewers. One small trial supports the oil on the skin for tension headache. One pharmacokinetic study explains the drug-interaction caution. No controlled trial has tested peppermint tea for everyday digestive comfort, so the traditional use rests on consistency across sources rather than on trial data.

Enteric-coated peppermint oil and irritable bowel syndrome

Ingrosso et al., Alimentary Pharmacology and Therapeutics, 2022 · Systematic review and meta-analysis of 10 randomized trials · Distilled oil in enteric-coated capsules

Design: 1,030 adults with IBS across 10 placebo-controlled trials, most 2 to 12 weeks long. Updates two earlier pooled analyses: Khanna (9 trials, 726 patients) and Alammar (12 trials, 835 patients).^11,12
Findings: peppermint oil beat placebo on global symptoms and on abdominal pain. About 4 people need to take the oil for one to improve on overall symptoms, and about 7 for one to improve on pain. Adverse events, mostly reflux, were more common with the oil.¹³
Dose: usually 0.2 ml oil per capsule, two to three times daily. Not tea, not leaf.
Limitations: the authors graded the certainty of evidence as very low because of small, short trials with results that varied widely between them. Several trials were manufacturer-funded. Blinding is imperfect since the oil's taste and menthol-scented stool can reveal the group. The largest recent trial, 190 patients over 8 weeks, missed its main goal of reducing abdominal pain, though secondary measures improved; the authors note one more large negative trial could tip the pooled result.¹⁴ Review funded by the authors' institutions; Ford has declared consultancy income from gut-drug companies.

Read the review

Topical peppermint oil and tension-type headache

Göbel et al., Der Nervenarzt, 1996 · Randomized double-blind placebo-controlled crossover · 10 percent oil in ethanol on skin

Design: 41 adults treated 164 tension headaches with peppermint solution, 1,000 mg acetaminophen, both, or placebo, each person trying every treatment in turn.
Findings: pain began to fall within 15 minutes of the peppermint application and the reduction matched acetaminophen over an hour.¹⁶ The EMA cited this and a companion study when it granted the oil well-established-use status for tension headache in 2020.⁶
Dose: 10 percent peppermint oil in 90 percent ethanol spread across the forehead and temples, repeated at 15 and 30 minutes. External only.
Limitations: one small trial at one German clinic, never repeated at scale. The placebo held a trace of peppermint to mask the smell, so it was not fully inert. Lichtwer Pharma supplied the test product. The Irish member of the EMA's herbal committee dissented from the 2020 monograph, stating the studies were too few and too small to support the claim.⁶

Read the study

Peppermint oil and drug metabolism

Dresser et al., Clinical Pharmacology and Therapeutics, 2002 · Randomized four-way crossover in 12 healthy volunteers · 600 mg distilled oil, single dose

Design: volunteers took the blood pressure drug felodipine with water, grapefruit juice, peppermint oil, or ascorbyl palmitate, with blood drug levels measured over the day, plus test-tube work on liver enzymes.
Findings: peppermint oil raised felodipine exposure to about 140 percent of the water condition, with wide variation between people. The mechanism is inhibition of CYP3A4, a gut and liver enzyme that breaks down roughly half of prescription drugs.¹⁵ The EMA records "some inhibition of CYP3A4" from this study and one on menthol.⁶
Dose: 600 mg of oil, roughly 30 drops, taken at once. Far above a cup of tea.
Limitations: 12 people, single dose, healthy volunteers only. Funded by AvMax Inc., a drug-delivery company with a commercial interest in absorption enhancers. A later study using 200 mg of pure menthol found no effect, so the interaction may only matter at high oil doses.¹⁹ Included because it is the basis of the medication caution below.

Read the study

Gas, cramping, and nausea: the traditional record

King's 1898, Ellingwood 1919, Grieve 1931, Commission E, EMA 2020, Health Canada · Consistent documentation, no controlled trial of the tea

Design: historical and regulatory records rather than a study. Every Western source on this page names the same short list: gas, cramping, upset stomach, nausea.^1,2,3,4,5,7
Findings: the EMA's leaf monograph rests on "long-standing use" and cites laboratory work showing leaf preparations relax gut muscle.⁵ The IBS trials give that tradition a plausible mechanism.
Dose: see the dosing table.
Limitations: no randomized trial has tested peppermint tea for these complaints. Agreement across sources is a form of evidence, but a weaker one than a controlled study, and the tea delivers far less oil than the capsules that were tested.

Read the EMA leaf monograph

Dosing Perspectives

Not medical advice. The doses below are educational. They show how different herbalists, traditions, and regulators have approached peppermint so you can see where they agree and where they differ. They are not a recommendation for you. Work with your healthcare provider or a clinical herbalist before using peppermint beyond food amounts, especially if you have reflux, gallstones, take medication, or are pregnant.

Source	Preparation	Dose (as stated)	Use
King's American Dispensatory (1898)	Infusion of the leaf; essence (1 fluid drachm of oil in 1 fluid ounce of alcohol)	Infusion "may be drank freely." Essence 10 to 60 drops in sweetened water	Internal; fresh bruised herb over the bowels or forehead, external
Ellingwood, American Materia Medica (1919)	Distilled oil; warm infusion	Oil 1 to 15 minims (drops)	Internal; oil applied locally for itching and toothache
German Commission E (1985 to 1990)	Dried leaf as infusion; tincture; distilled oil; enteric-coated oil	Leaf 3 to 6 g daily; tincture 5 to 15 g daily; oil 6 to 12 drops daily; enteric-coated 0.6 ml daily; 3 to 4 drops in hot water for inhalation	Internal; oil also external and inhaled
European Medicines Agency, leaf monograph (2020)	Dried leaf as infusion; tincture 1:5 in 45 or 70 percent ethanol	Adults 1.5 to 3.0 g in 100 to 150 ml boiling water, 3 times daily; tincture 2.0 to 3.0 ml, 3 times daily. Children 4 to 11: 1.0 to 2.0 g, 3 times daily. Not under 4	Internal
European Medicines Agency, oil monograph (2020)	Enteric-coated capsules; 10 percent oil in ethanol; inhalation; creams 5 to 20 percent	Capsules 0.2 to 0.4 ml per dose, 0.6 to 1.2 ml daily, 30 minutes before meals, up to 3 months; children 8 to 11: 0.2 ml 3 times daily. Headache: one application, repeatable twice at 15-minute intervals, adults only. Inhalation 0.08 to 0.16 ml up to 3 times daily	Internal (capsules); external (headache, muscle pain, itch); inhaled (colds)
Health Canada monograph (2026)	Dried leaf; distilled oil	Adults 1.2 to 12 g leaf daily; 60 to 800 microliters oil daily (about 1 to 16 drops). Children 2 to 4 years: 0.2 to 2 g leaf daily	Internal
David Hoffmann, Medical Herbalism (2003)	Tincture 1:5 in 40 percent alcohol; infusion	Tincture 1 to 2 ml 3 times daily; 1 heaped teaspoon dried leaf per cup, covered, 10 minutes	Internal; cooled infusion external for itch
Bensky, Chinese Herbal Medicine: Materia Medica	Bo He (Mentha haplocalyx) in decoction, added in the last minutes	3 to 6 g	Internal; different species and different indications, see Traditional Use

The spread from 1.2 g to 12 g of leaf a day is not carelessness. Health Canada's floor treats peppermint as a flavor and a mild aromatic. Its ceiling is the strong infusion used in British practice, where three cups of a heaped teaspoon each adds up to about 5 g. The EMA sits between, at up to 9 g a day. The oil rows are a separate scale: Ellingwood's 15 drops and the EMA's 1.2 ml daily describe roughly the same ceiling in different units, and both are many times what a cup of tea delivers.

Preparations by What You Want to Extract

King's put it plainly in 1898: peppermint's virtues "are taken up in infusion by water, and still better by alcohol."¹ The volatile oil carries most of the action and dissolves poorly in water, so each preparation below is ranked by how well it captures the oil. If the methods are new to you, start with my article on decoctions versus infusions.

Solubility of the constituents

Volatile oil (menthol, menthone): alcohol and fat. Poorly soluble in water. Leaves with the steam from an open cup.¹
Rosmarinic acid and flavonoids: water and alcohol. A hot infusion pulls these fully.
Tannins: water. Longer steeps pull more, which is why a 20-minute cup tastes drier than a 10-minute one.

Preparations that fit the chemistry

Tincture, 1:5 in 40 to 70 percent alcohol. The best home preparation for the oil, and it also carries the water-soluble phenolic acids and flavonoids. The EMA lists both 45 and 70 percent ethanol; Hoffmann uses 40 percent. Shelf stable for years and dosed by the milliliter.^5,8
Enteric-coated oil capsules. The form used in nearly all IBS trials. The coating carries the oil past the stomach into the intestine, which is why heartburn is less common than with plain oil. A manufactured product, not a home preparation, and it carries every oil caution in the Safety section. The EMA says to swallow them whole, 30 minutes before meals, and not alongside antacids or acid-blocking drugs, which dissolve the coating early.⁶
Covered hot infusion. One heaped teaspoon (about 1.5 g) of dried leaf per cup of just-boiled water, covered, 10 minutes. Water pulls the rosmarinic acid, flavonoids, and tannins and holds some oil as long as the lid stays on. Grieve and Hoffmann both insist on the cover; an uncovered cup smells wonderful because the medicine is leaving.^3,8 This is the everyday form and the one that tastes best.
Steam inhalation. 3 to 4 drops of oil in a bowl of hot water, breathed with a towel over the head, uses the oil's volatility on purpose.⁴ The EMA's traditional-use range is 0.08 to 0.16 ml per session, adults and adolescents only.⁶
Topical dilution. The headache trial used 10 percent oil in ethanol on the temples.¹⁶ The EMA's cream range for muscle pain and itch is 5 to 20 percent in oil or salve for adults.⁶ Keep it away from the eyes and off the faces of children. A cooled strong infusion on a cloth is a gentler option for hot, itchy skin.
Essence. King's essence of peppermint, one part oil to eight parts alcohol, was the Eclectics' usual internal form, dosed by the drop in sweetened water.¹ It is a diluted oil, so the oil cautions apply.

Preparations to skip

Decoction. Boiling the leaf drives off the oil. Bensky adds Bo He in the last minutes of a decoction for exactly this reason.¹⁰
Undiluted essential oil by mouth. Outside an enteric-coated product this is a route to heartburn, and in children, to airway spasm. The EMA's overdose section lists seizures, loss of consciousness, and heart rhythm disturbance from menthol at high doses.⁶
Glycerite as the main preparation. Glycerin extracts the oil poorly. It works as a sweet carrier for a tincture, not as a substitute for one.

Safety and Cautions

Not medical advice. Herbs contain active compounds that can interact with medications and health conditions. Peppermint leaf tea in food amounts is one of the safest herbs in common use, and the EMA reports no overdose ever recorded for the leaf. The concentrated oil is a different substance: the EMA lists seizures, loss of consciousness, and heart rhythm disturbance among overdose effects, all attributed to menthol.^5,6 Most cautions below apply to the oil. Where Francis Brinker grades a caution as empirical (observed in practice) or speculative (reasoned from mechanism), that grade is given in parentheses.²¹ Talk with your healthcare provider or pharmacist before using peppermint beyond tea if any of these apply to you.

Digestive tract

Reflux and heartburn. Menthol relaxes smooth muscle, including the ring of muscle between stomach and esophagus that keeps acid down, an effect measured in a human study of the oil.²¹ The EMA's leaf monograph says people with gastroesophageal reflux "should avoid peppermint leaf preparations, because heartburn may increase," and Brinker lists persistent GERD as a contraindication (speculative) on the same mechanism.^5,21 The oil monograph says anyone with heartburn who worsens on oil capsules should stop.⁶ Heartburn was the most common side effect in the IBS trials.¹³ Chamomile or fennel are the traditional alternatives.
Hiatal hernia. Brinker lists it as a separate contraindication (speculative), citing the sphincter-relaxing effect of the oil.²¹ The EMA groups it with heartburn.⁶
Gallstones and bile duct disease. Peppermint increases bile flow. Brinker says do not use with gallstones without consulting a physician (speculative), and Commission E says the same for the leaf.^4,21 The EMA lists gallstones and other biliary disorders as a caution for the leaf and a contraindication for oil capsules, along with liver disease, cholangitis, and achlorhydria (absence of stomach acid).^5,6
Inflamed or ulcerated gut. The EMA says oil should be used with caution in inflamed and ulcerated conditions of the digestive tract, and Ellingwood's rule was to avoid peppermint where the abdomen is tender and the tongue is red-tipped, his signs of active inflammation.^2,6
Oil capsule side effects. Beyond heartburn, the EMA lists perianal burning, blurred vision, dry mouth, nausea, and vomiting as frequent in trials, plus menthol-scented urine and stool. Chewing or breaking a capsule releases the oil in the mouth and esophagus and causes local irritation.⁶

Children

Never apply oil or menthol near the face of a baby or small child. Brinker: the oil should not be inhaled by or applied to the face or nose of infants or small children (empirical) because menthol may cause spasm of the glottis (empirical).²¹ The EMA contraindicates the oil under age 2 for reflex apnea (a pause in breathing) and laryngospasm (spasm of the vocal cords), and in any child with a history of seizures, febrile or not. Commission E and Hoffmann carry the same warning.^4,6,8
Leaf tea. The sources disagree on a starting age. Health Canada's ranges begin at 2. The EMA does not recommend the leaf under 4 for lack of data, and does not recommend oil capsules under 8.^5,6,7

Medications

Drugs cleared by CYP3A4. A single 600 mg dose of oil raised felodipine exposure to 140 percent in 9 men and 3 women, an effect Brinker compares to grapefruit juice (PO in human study), in a trial funded by a company with a commercial interest.^15,21 The counter-evidence Brinker gives: pure menthol in successive doses of 100, 50, 25, and 25 mg had no effect on felodipine in 11 people (PO in human study), and the oil's inhibition of nifedipine metabolism was reversible in liver cells (in vitro).²¹ The EMA records "some inhibition of CYP3A4" from the oil, and the leaf monograph reports no interactions.^5,6 If you take a drug with a narrow safety margin, keep peppermint to occasional tea and ask your prescriber before using oil capsules.
Cyclosporine. Peppermint oil at 50 and 100 mg per kg raised cyclosporine peak levels and bioavailability 2 to 3 times in rats; Brinker notes the doses were above human doses but the blood levels and dose ratio were similar to human use (PO in rats).²¹ A 2005 case series in transplant patients involved multi-herb tea blends, one containing peppermint, so it cannot be pinned on peppermint.¹⁸ Transplant patients should treat peppermint oil as off limits without their prescriber.
Warfarin, low confidence. Two case reports describe INR (a clotting measure) falling in people who used 6 to 10 menthol cough drops daily for 4 days or 3 weeks after starting warfarin; INR recovered when the drops stopped (PO in human case reports). Brinker's own analysis: menthol has no effect on the enzymes that would explain it, only two cases exist among the many people who combine the two, and the response is "extremely rare and likely idiosyncratic, if menthol is involved at all."²¹ Included so anyone on warfarin can mention it to their pharmacist.
CYP1A2 and CYP2E, rat data. A 2 percent peppermint tea drunk for 4 weeks reduced phenacetin metabolism to 24 percent of normal and CYP2E activity to 60 percent (PO in rats).²¹ Menthol had no effect on the CYP1A2 probe caffeine in humans, so the rat finding has not carried into people.²¹
Antacids, H2 blockers, and proton pump inhibitors. These dissolve the enteric coating early, releasing the oil in the stomach. The EMA says to avoid taking them with oil capsules.⁶
Iron, minerals, and thiamine. Tea made with 3 g of leaf per cup reduced non-heme iron absorption in a human study, which Brinker attributes "likely" to the flavonoids (PO in human study); his separate note gives the tannins as a speculative reason peppermint may reduce absorption of metal ions, thiamine, and alkaloids taken at the same time.²¹ Health Canada attributes the iron effect to tannins and flags anemia as a reason to ask a practitioner first.⁷ Taking tea between meals rather than with them sidesteps the question.

Pregnancy and nursing

The sources split four ways. Brinker says excessive use should be avoided in early pregnancy (speculative) because of an emmenagogue effect, meaning an action that stimulates menstrual flow, which he grades empirical.²¹ Hoffmann and Grieve treat peppermint tea as an ordinary household herb with a long record of use, including for morning sickness.^3,8 The EMA's 2020 monographs state that safety in pregnancy and lactation "has not been established" and do not recommend use.^5,6 Health Canada says to consult a health care practitioner before use.⁷ Read together: ordinary tea has tradition behind it, "excessive" use and the oil do not, and the regulators are recording absent data rather than evidence of harm. Ask your provider.

Nursing. Brinker says the essential oil should not be used by nursing mothers without professional advice (speculative) because it may reduce milk secretion, and the EMA notes it is unknown whether oil constituents pass into breast milk.^6,21 That concern is about the oil; the leaf has a traditional reputation for drying secretions in large amounts, which is the same caution stated more mildly.

Skin, allergy, and inhalation

Contact sensitivity. Brinker: avoid oral exposure in anyone with contact sensitivity reactions to peppermint oil or menthol, especially when those reactions have produced mouth ulcers (empirical).²¹ Menthol is in toothpaste, gum, and lozenges, so this group is larger than it sounds.
Undiluted oil irritates skin and must not go on broken or irritated skin. Contact dermatitis, rash, and eye irritation from unwashed hands are reported. Anyone allergic to menthol or the mint family should avoid peppermint.⁶
Rare allergic reactions to menthol taken by mouth include headache, slowed heart rate, muscle tremor, and anaphylaxis, frequency unknown.⁶
Inhalation has caused apnea and airway constriction in hypersensitive people. Large inhaled doses of menthol can cause dizziness, confusion, and double vision.⁶

Pulegone and menthofuran

Two oil constituents caused liver and urinary tract tumors in rodents at high doses. The EMA limits daily exposure to 37.5 mg per adult and 0.75 mg per kg for children and requires oil products to declare their content.⁶ Peppermint oil runs 1 to 11 percent pulegone and menthofuran combined, so a full day's capsule dose of 1.2 ml can approach the limit at the high end of that range. Tea delivers a small fraction of this. It is a reason to buy oil capsules from makers who state the figures, not a reason to avoid the leaf.

Studied combinations

Luteolin, a flavonoid in peppermint, reduced the heart toxicity of the chemotherapy drug doxorubicin in mice, and water extracts of the fresh herb showed antimutagenic activity in the lab (PO in mice; in vitro).²¹ Animal and test-tube data only. Anyone in cancer treatment should clear every herb with their oncology team, since the CYP3A4 findings above cut the other way for some chemotherapy drugs.

Energetic caution

Peppermint dries and disperses. Practitioners who apply energetic categories keep it away from people who are chronically cold, thin, and depleted, and Bensky's contraindications for Bo He, spontaneous sweating and yin deficiency with heat, describe the same pattern in Chinese terms.¹⁰ Warming, moistening herbs suit that constitution better.

Frequently Asked Questions

Does peppermint tea help with digestion?

Every Western herbal tradition on record uses it for gas, cramping, and an upset stomach, and European regulators accept that use on the strength of the historical record. Laboratory work shows the leaf relaxes gut muscle. No controlled trial has tested the tea itself, so the answer rests on consistent tradition and a plausible mechanism rather than trial data.

Is peppermint good for acid reflux?

No. Menthol relaxes the muscle that keeps stomach acid down, heartburn was the most common side effect in the oil trials, the EMA says people with reflux should avoid peppermint leaf preparations, and Brinker lists persistent GERD and hiatal hernia as contraindications. Chamomile and fennel are the traditional alternatives for a sour stomach.

Can I drink peppermint tea every day?

Health Canada's adult range runs to 12 g of leaf a day and the EMA's to 9 g, with the EMA advising a check-in with a practitioner if digestive symptoms last beyond 2 weeks. Daily tea sits well inside those figures for most people. Reflux, gallstones, iron-deficiency anemia, pregnancy, and narrow-margin medications are the reasons to ask first.

Does peppermint interact with medications?

The oil does, at capsule doses: a 600 mg dose raised blood levels of the blood pressure drug felodipine about 40 percent in one small study, and rat data show the same for cyclosporine. Two case reports link menthol cough drops to reduced warfarin effect, which Brinker judges rare and probably not caused by menthol. The leaf tea has no reported drug interactions in the EMA monograph, though it can reduce iron absorption when drunk with meals. If you take any prescription drug, ask your pharmacist before oil capsules.

What is the difference between peppermint and spearmint?

Spearmint is one of peppermint's two parents. Its oil is mostly carvone, which is sweet and does not trigger the cold receptors, while peppermint oil is mostly menthol. Spearmint is the milder digestive tea and the one more often given to children; peppermint carries the stronger antispasmodic action and all the oil cautions on this page.

Is peppermint safe for pets?

The oil is not. Cats lack the liver enzymes to clear many essential oil constituents, and menthol can cause breathing trouble in small animals. Keep oil, menthol rubs, and diffusers away from cats, dogs, and birds. A few leaves in a dog's water are unlikely to cause harm, but there is no veterinary reason to give them. Ask your veterinarian before using any herb on an animal.

Can I take peppermint oil capsules for IBS?

That is a question for your doctor, because IBS is a diagnosis that requires ruling out other conditions first. What the research shows: enteric-coated oil beat placebo for overall symptoms and pain across 10 trials, the reviewers rated the certainty as very low, and heartburn was the trade-off. The EMA approves the capsules for adults and children over 8, for up to 3 months per course, taken whole 30 minutes before meals.

Why does peppermint feel cold?

Menthol binds TRPM8, the receptor on nerve endings that normally responds to cool temperatures, so the brain reads it as cold even when nothing has changed. King's noted the warm, burning taste that comes first and the coolness that follows on inhaling, and both are correct: the plant is a warming stimulant that produces a cold sensation.

Sources

Felter HW, Lloyd JU. Mentha Piperita (U.S.P.), Peppermint. King's American Dispensatory, 1898. Public domain, hosted at Henriette's Herbal. Companion entries: Oil of Peppermint and Spirit of Peppermint.
Ellingwood F. Mentha piperita. The American Materia Medica, Therapeutics and Pharmacognosy, 1919. Public domain, hosted at Henriette's Herbal.
Grieve M. Mints. A Modern Herbal, 1931. Hosted at botanical.com.
German Commission E monographs, Peppermint leaf (1985, revised 1990) and Peppermint oil (1986, revised 1990). In: Blumenthal M, ed. The Complete German Commission E Monographs. American Botanical Council, 1998. ABC Expanded Commission E, Peppermint leaf; Peppermint oil. ABC is a nonprofit funded in part by industry membership.
European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Mentha x piperita L., folium. Final, Revision 1. EMA/HMPC/572705/2014, adopted 15 January 2020.
European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Mentha x piperita L., aetheroleum. Final, Revision 1. EMA/HMPC/522410/2013, adopted 15 January 2020. Source of oil dosing, contraindications, adverse effects, overdose, and pulegone and menthofuran limits. The dissenting opinion on tension headache is in the HMPC opinion, Appendix II.
Health Canada, Natural and Non-prescription Health Products Directorate. Peppermint, Mentha x piperita monograph. Updated February 27, 2026. Cites Mills and Bone 2005, ESCOP 2003, Bradley 1992, Brinker 2010.
Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press, 2003 (affiliate link). Mentha piperita entry.
Pole S. Ayurvedic Medicine: The Principles of Traditional Practice. Elsevier, 2006 (affiliate link). Mint entry. .
Bensky D, Clavey S, Stöger E. Chinese Herbal Medicine: Materia Medica, 3rd edition. Eastland Press, 2004. Bo He (Menthae haplocalycis Herba) entry.
Khanna R, MacDonald JK, Levesque BG. Peppermint oil for the treatment of irritable bowel syndrome: a systematic review and meta-analysis. Journal of Clinical Gastroenterology. 2014;48(6):505-512. DOI: 10.1097/MCG.0b013e3182a88357.
Alammar N, Wang L, Saberi B, et al. The impact of peppermint oil on the irritable bowel syndrome: a meta-analysis of the pooled clinical data. BMC Complementary and Alternative Medicine. 2019;19:21. DOI: 10.1186/s12906-018-2409-0.
Ingrosso MR, Ianiro G, Nee J, Lembo AJ, Moayyedi P, Black CJ, Ford AC. Systematic review and meta-analysis: efficacy of peppermint oil in irritable bowel syndrome. Alimentary Pharmacology and Therapeutics. 2022;56(6):932-941. DOI: 10.1111/apt.17179. Evidence graded very low certainty by the authors.
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;158(1):123-136. DOI: 10.1053/j.gastro.2019.08.026. Funded by ZonMw, the Dutch government health research organization; capsules supplied by the manufacturer.
Dresser GK, Wacher V, Wong S, Wong HT, Bailey DG. Evaluation of peppermint oil and ascorbyl palmitate as inhibitors of cytochrome P4503A4 activity in vitro and in vivo. Clinical Pharmacology and Therapeutics. 2002;72(3):247-255. DOI: 10.1067/mcp.2002.126409. Funded by AvMax Inc.
Göbel H, Fresenius J, Heinze A, Dworschak M, Soyka D. Effectiveness of Oleum menthae piperitae and paracetamol in therapy of headache of the tension type. Der Nervenarzt. 1996;67(8):672-681. German language. DOI: 10.1007/s001150050040. Test product supplied by Lichtwer Pharma.
Hills JM, Aaronson PI. The mechanism of action of peppermint oil on gastrointestinal smooth muscle: an analysis using patch clamp electrophysiology and isolated tissue pharmacology in rabbit and guinea pig. Gastroenterology. 1991;101(1):55-65. DOI: 10.1016/0016-5085(91)90459-Y. Animal tissue; supported by Tillotts Pharma, maker of an enteric-coated peppermint product.
Nowack R, Nowak B. Herbal teas interfere with cyclosporin levels in renal transplant patients. Nephrology Dialysis Transplantation. 2005;20(11):2554-2556. DOI: 10.1093/ndt/gfi003. Case series; teas were multi-herb blends.
Memorial Sloan Kettering Cancer Center, About Herbs. Peppermint. Institutional summary of interaction reports, including Gelal 2005 (menthol and felodipine). Secondary source.
Remington JP, Wood HC, editors. Mentha Piperita. Peppermint. The Dispensatory of the United States of America, 1918. Public domain, hosted at Henriette's Herbal.
Brinker F. Herbal Contraindications and Drug Interactions, 4th edition. Eclectic Medical Publications, 2010. Peppermint entry, pp. 261-262. Evidence grades (empirical, speculative, PO in human study, PO in rats, in vitro) are his.

This monograph is updated as new research and sources become available.

Ivy Ham

I'm Ivy Ham, a clinical herbalist dedicated to blending traditional healing wisdom with modern science, and revealing how nature's remedies can enhance everyday wellness. Through my blog, I share insights on herbal solutions, nutrition, and holistic practices to guide you toward a more balanced, vibrant life.

Certified clinical herbalist · Missoula, Montana · Read more about Ivy