English Horsemint Drug Interactions, Uses, Effectiveness, Safety & More

English horsemint (Mentha longifolia) is a type of wild mint in the same plant family as peppermint and spearmint. It is a perennial herb native to Europe, Asia, and parts of Africa, and it grows in moist places like stream banks and ditches. The plant has square stems, aromatic dark green leaves, and spikes of small pink to purple flowers.

People have long used this mint in cooking and folk medicine. The leaves are brewed into tea or used as a flavoring, and the plant also yields an aromatic essential oil. In traditional practice it is used mainly to ease digestive and respiratory complaints.

It is worth noting that Mentha longifolia is a different plant from American horsemint (Monarda punctata), even though both are sometimes called "horsemint."

Like other mints, English horsemint contains aromatic compounds in its essential oil, including menthol, menthone, pulegone, and related terpenes. The exact mix varies by plant variety and growing conditions.

These compounds are thought to relax the smooth muscle of the gut, which may help with cramping and gas, and to give the herb its cooling, soothing feel. Laboratory studies also suggest the oil can slow the growth of certain bacteria, fungi, and possibly act as an antioxidant.

It is important to remember that most of this information comes from test-tube and animal research. How well these effects translate to real benefits in people is not well established.

Used as a food or normal tea amount, English horsemint is generally considered well tolerated by most healthy adults. Concentrated extracts and especially the essential oil are much stronger and carry more risk; the oil should never be swallowed undiluted.

Some mint oils naturally contain pulegone, a compound that can be toxic to the liver in large amounts. For this reason, large or long-term doses of concentrated products are not advised. People with reflux (GERD) may find mint worsens heartburn.

For safety, pregnant and breastfeeding people should avoid medicinal amounts and the essential oil, since there is not enough reliable information to confirm it is safe. Children, older adults, and people with liver disease, gallbladder problems, or other chronic conditions should check with a pharmacist or doctor first. Keep essential oils away from infants and young children.

In food-like amounts, side effects are uncommon. When they occur, they may include heartburn, mild stomach upset, or allergic reactions in people sensitive to plants in the mint family.

The essential oil is more likely to cause problems. Applied to the skin it can cause irritation, and taken by mouth in large amounts it may cause nausea or, rarely, more serious effects linked to compounds like pulegone. Stop use and seek medical care if you have trouble breathing, swelling, a rash, or signs of an allergic reaction.

There is no well-established standardized dose for English horsemint. It is most commonly used as a tea made from the dried or fresh leaves, or as a flavoring in food.

Because product strengths vary widely, the best advice is to follow the directions on the product label and not exceed them. Essential oils are highly concentrated and should be used only as directed, well diluted, and never swallowed without professional guidance.

When in doubt, ask a pharmacist or doctor about whether and how to use it, especially if you take other medicines or have a health condition.