Mentha includes about two dozen recognized species of aromatic herbs, in addition to numerous hybrids and cultivars. Peppermint is a sterile hybrid of M. aquatica (water mint) and M. spicata (spearmint). It spreads vegetatively via creeping rhizomes and is widely distributed both in the wild and in cultivation, where it can be propagated from cuttings. Raw peppermint leaves enhance salads and are a key component of tabbouleh (the famous Lebanese bulghur and parsley salad). In many cuisines, peppermint is also used to flavor cooked dishes; for example, mint is supposed to go well with lamb. Peppermint tea is a pleasant beverage; in North Africa, black tea is commonly blended with peppermint. Peppermint can be used to flavor sweets, candies, and alcoholic beverages, though most peppermint candies no longer contain real peppermint extract. Many flavorful mint species are used as teas for both medicinal and beverage purposes; peppermint is one of very few that contains large amounts of menthol, which provides the cooling sensation. Peppermint tea is used medicinally for stomach upsets, gas, colds, headaches, and nervous tension. Topical application of highly diluted peppermint essential oil is used to treat headache, and menthol is an ingredient in various products used to relieve congestion.

Dozens of human studies using peppermint oil capsules and combination products including peppermint have shown that peppermint?s antispasmodic effect on the digestive tract can alleviate symptoms of irritable bowel syndrome and non-ulcer dyspepsia. Moreover, topical use of peppermint oil during colonoscopy greatly reduces colonic spasm. No studies have been done using peppermint tea, perhaps because of the impossibility of creating a completely indistinguishable yet inert placebo. It is fair to assume that the traditionally reported benefits now demonstrated for other products are in fact present in the tea. One study has found that exposure to peppermint odor improves performance of clerical tasks. Peppermint oil has at most mild side effects, including heartburn; it may exacerbate acid reflux and hiatal hernia. Peppermint tea, a popular conventional beverage, is very safe. Menthol-rich products should not be given to young infants or applied to their faces, because they can reflexively stop breathing. A few people have claimed that pregnant women should avoid peppermint, but no evidence supports this. One related species, pennyroyal (Mentha pulegium), has been used to induce miscarriage, but it is chemically quite unlike peppermint; it contains toxic compounds and tastes unpleasant. Extensive human use indicates that consumption of normal culinary quantities of peppermint poses no significant risk. Like all essential oils, peppermint essential oil should not be taken orally.

Selected References

Barker, S., P. Grayhem, J. Koon, J. Perkins, A. Whalen, and B. Raudenbush. 2003. Improved performance on clerical tasks associated with administration of peppermint odor. Percept. Mot. Skills 97:1007-1010.

Bunsawat, J., N. E. Elliott, K. L. Hertweck, E. Sproles, and L. A. Alice. 2004. Phylogenetics of Mentha (Lamiaceae): evidence from chloroplast DNA sequences. Syst. Bot. 29:959-964.

Gobert, V., S. Moha, M. Colson, and P. Taberlet. 2002. Hybridization in the section Mentha (Lamiaceae) inferred from AFLP markers. Amer. J. Bot. 89:2017-2023.

Grigoleit, H. G., and P. Grigoleit. 2005. Peppermint oil in irritable bowel syndrome. Phytomedicine 12:601-606.

Harley, R. M. 1972. Mentha. Pp. 183-186 in: T. G. Tutin et al., eds. Flora Europaea, vol. 3. Cambridge University Press, Cambridge.

McKay, D. L., and J. B. Blumberg. 2006. A review of the bioactivity and potential health benefits of peppermint tea (Mentha piperita L.). Phytother. Res. 20:619-633.

Thompson Coon, J., and E. Ernst. 2002. Systematic review: herbal medicinal products for non-ulcer dyspepsia. Aliment. Pharmacol. Ther. 16:1689-1699.

Voirin, B., C. Bayet, O. Faure, and F. Jullien. 1999. Free flavonoid aglycones as markers of parentage in Mentha aquatica, M. citrata, M. spicata, and M. × piperita. Phytochemistry 50:1189-1193.