Peppermint leaves: food uses, tea research and precautions

Identity and the form used

Peppermint is Mentha × piperita L., a hybrid in the Lamiaceae family. This reference covers identified, cultivated food-grade leaves, fresh or dried, used as seasoning or an ordinary infusion. Spearmint (Mentha spicata) and pennyroyal (Mentha pulegium) are not interchangeable substitutes. A mint-like smell alone does not identify a safe food plant. [1] [2]

Its practical value at the table

The leaves provide aroma and flavour. Try a little chopped leaf in a dish or prepare an unsweetened infusion according to the food product's instructions. This is a way to vary flavours, not a prescribed daily treatment. Adding sugar changes the drink; adding essential oil changes the preparation altogether. [2]

Laboratory analysis has identified aromatic compounds and polyphenols in peppermint infusion, with different extraction of different constituents. Therefore, a measurement in dry leaves or distilled oil is not a nutrient label for your cup. The presence of plant compounds does not by itself establish a clinical benefit. [4]

Preparation and storage

Use clean utensils, remove damaged or dirty leaves, and rinse fresh herbs under running water without soap or bleach. Chop shortly before use to preserve aroma. Keep dried herbs in a labelled, tightly closed container in a cool, dry, dark place; follow the product's storage instructions. [3]

For tea, follow the package directions and strain loose leaves. Let the drink cool to a comfortable temperature. Do not intensify a brew to reproduce a medicine's dose: research on a measured preparation is not a household dosing guide. Keep the original label when a mixture contains other herbs, so all ingredients can be checked.

Common claims: what does the evidence show?

“Peppermint tea gives lasting memory improvement.” — Preliminary, not established. A 2025 study by researchers at Northumbria University in Newcastle upon Tyne, UK, randomly assigned 25 adults to peppermint tea or warm water presented as containing a flavourless peppermint extract. Tests were repeated after a short interval. Memory and attention performance and measures of brain blood flow improved more in the tea group, but blood-flow changes did not explain the cognitive changes. [5]

The experiment used 200 mL of tea and assessed participants after 20 minutes. It was small, single-blind and based on a convenience sample. Diet, caffeine and activity were not measured, and sustained effects were not tested. These findings do not demonstrate dementia prevention or treatment of cognitive impairment, and the research amount is not a therapeutic recommendation. [5]

“A cup of tea has the same evidence as peppermint-oil capsules for irritable bowel syndrome.” — No. An eight-week Dutch trial analysed 189 patients receiving one of two oil formulations or placebo. Neither oil met the primary response outcomes; one formulation improved some secondary symptom measures, while mild adverse events were more frequent with oils. This mixed result concerns capsules, not leaf tea, and cannot establish equivalent benefits from a cup. [6]

Tolerance and important cautions

More is not necessarily better: NC State notes vomiting and diarrhoea after large ingestions. Peppermint tea may worsen heartburn. Reduce or avoid it when it repeatedly triggers reflux rather than using it to treat those symptoms. [1] [13]

Do not self-treat gallbladder symptoms with concentrated oil. A small experiment in 12 healthy volunteers found altered gallbladder emptying after peppermint oil; it did not establish the safety or effectiveness of leaf tea for gallbladder disease. [8]

Severe peppermint allergy has been documented in a case report; this does not tell us how common it is. Avoid a known trigger and do not test a suspected allergy at home. Breathing difficulty, throat swelling or faintness requires emergency help and prescribed adrenaline according to the person's plan. [9] [10]

Medicines, pregnancy and children

A German case report linked a nine-herb tea containing peppermint to changes in cyclosporin levels in a kidney-transplant recipient. The responsible ingredient was unresolved: it is not proof that pure peppermint tea caused the effect. People taking transplant medicines should discuss starting, stopping or substantially changing herbal drinks with their treatment team; do not adjust the medicine yourself. [7]

The adult trials above do not establish medicinal doses or long-term safety during pregnancy, breastfeeding or childhood. Routine seasoning and repeated concentrated use are different exposures. Ask for individual advice before medicinal use in these circumstances. Essential oils need separate assessment: do not add aromatherapy oils to drinks or apply undiluted oils to children. Keep bottles out of their reach. [12] [11]

Conclusion

Choose peppermint leaves for their culinary flavour, and judge a tea by its actual ingredients and your tolerance. Promising short-term research is worth following, but it does not turn a familiar infusion into an established treatment or make concentrated oil equivalent to food.