The Evidence for Herbal and Botanical Remedies, Part 1

Musculoskeletal pain. A small study comparing topical menthol to ice for muscle soreness noted decreased perceived discomfort with menthol.⁵⁴ Menthol has also been shown to reduce pain in patients with knee OA.⁵⁵

Carpal tunnel syndrome (CTS). A triple-blind RCT concluded that topical menthol acutely reduced pain intensity in slaughterhouse workers with CTS, and it should be considered as an effective nonsystemic alternative to regular analgesics in the workplace management of chronic and neuropathic pain.⁵⁶

Adverse effects

Peppermint appears to be safe for most adults when used in small doses, and serious adverse effects are rare.^43,57 While peppermint tea appears to be safe in moderate-to-large amounts, people allergic to plants in the peppermint family (eg, mint, thyme, sage, rosemary, marjoram, basil, lavender) may experience allergic reactions with swelling, wheals, or erythema. Peppermint may also cause heartburn due to relaxation of the cardiac sphincter.

Other symptoms may include nausea, vomiting, flushing, and headache.⁵⁸ The herb may also be both hepatotoxic and nephrotoxic at extremely high doses.⁵⁹ Other considerations for women are that it can trigger menstruation and should be avoided during pregnancy. Due to uncertain efficacy in this population, peppermint oil should not be used on the face of infants, young children, or pregnant women.^58,59

The bottom line

Peppermint appears to be safe and well tolerated. It is useful in alleviating IBS symptoms and may be effective in the treatment of non-ulcerative dyspepsia, musculoskeletal pain, headache, and CTS.^54,55