Nutrients
Peppermint is an excellent source of vitamin C and vitamin A. Peppermint is a very good source of magnesium, folate, dietary fiber, calcium, iron, and vitamin B2.

Irritable Bowel Syndrome
In a 1-month double blind, placebo-controlled clinical study involving 110 participants with symptoms of irritable bowel syndrome, there was significant improvement of symptoms after taking a peppermint oil formulation 3 to 4 times daily.
In another study 57 participants were given peppermint oil capsules twice daily for 4 weeks, and 75% of the participants showed a 50% decrease of irritable bowel syndrome symptoms.

Indigestion (dyspepsia)
An herbal preparation consisting of peppermint oil and caraway has been shown to alleviate pain associated with dyspepsia, and a reduction in other gastrointestinal symptoms.
The peppermint oil and caraway combination appears to be as effective as Cisapride (withdrawn because of harmful side effects) in relieving dyspepsia.

Headache
At the Neurological Clinic at the University of Kiel in Germany, a topical application of peppermint oil and ethanol produced a reduction in sensitivity to headache.
Another study has shown that a topical application of peppermint oil and ethanol combination rubbed on the forehead and temples to be just as effective in alleviating tension headache as acetaminophen (Tylenol).

Shingles
A 76-year-old woman shingles sufferer experienced almost immediate relief from pain after topical treatment with peppermint oil. Standard therapies had been ineffective in relieving her pain.

Anti Cancer
Perillyl alcohol is a dietary monoterpene (phytochemical or phytonutrient) found in the essential oil of peppermint and other plants. Preliminary studies have shown perillyl alcohol to regress pancreatic, mammary, and liver tumors, and has the ability to kill cancer cells without harming healthy cells. Results of this and other studies suggest that perillyl alcohol may have potential as a non-toxic preventative treatment for various types of human cancers.
Rosmarinic acid is a phenolic acid found in peppermint and other herbs, which has antioxidant activities stronger than that of vitamin E, helping to reduce cell damage and the risk of cancer.

Candidiasis
Of 35 oil extracts of medicinal plants tested, peppermint was one of the 13 plants that demonstrated anti-Candida activity.

Athletes Foot
A study at the University of Novi Sad in Yugoslavia has shown peppermint oil to have greater fungicidal activity than the commercial fungicide Bifonazole, which is used to treat the fungal skin infection athlete’s foot.