Does Peppermint Oil Have Antifungal or Antimicrobial Properties?

 For centuries, healers have turned to peppermint for its fragrant and medicinal properties. In modern naturopathy, peppermint remains a popular treatment option for heartburn, tension headache, irritable bowel syndrome and other medical conditions. Some evidence suggests that peppermint oil also possesses antibacterial properties. More research is needed to identify specific medicinal benefits associated with peppermint oil.

In Vitro Evidence

According to the University of Maryland Medical Center, or UMMC, peppermint oil demonstrates antibacterial properties in laboratory settings. These investigations, known as in vitro studies, suggest that peppermint oil directly disrupts several forms of living bacteria. It either kills these pathogens or disrupts their reproduction, thereby preventing their spread. However, peppermint oil may behave differently in the human body than it would behave in a test tube or petri dish. For this reason, in vitro studies are not considered to be reliable evidence of its specific disease-fighting properties.

Human Studies

Few human clinical trials have investigated peppermint oil's potential as an agent for combating bacterial or fungal infections. The UMMC notes that peppermint oil appears to soothe skin itching and irritation, which are common symptoms of superficial infection. However, peppermint oil has only been clinically investigated as a topical treatment for hives, poison ivy, poison oak and shingles. The UMMC also acknowledges human clinical evidence that peppermint oil can defeat symptoms of upper-respiratory infections, but attributes the benefits to decongestant, rather than antibacterial, properties.

Antifungal Properties

Neither the National Institutes of Health nor the University of Maryland Medical Center acknowledge any scientific evidence suggesting that peppermint oil can fight fungal infections. Although some naturopaths may suggest it as a complementary treatment for fungal skin infections, such as athlete's foot, evidence that it works is currently lacking. More in vitro studies and clinical trials will be necessary to determine if peppermint oil can treat fungal infections.

Medicinal Applications

Despite a lack of conclusive scientific evidence, some people may choose to use peppermint oil internally or externally to fight bacterial or fungal infections. According to the National Institutes of Health, a daily dose of 90 mg of peppermint oil capsules appears to be generally safe for internal use. Most peppermint capsules are made with an enteric coating, which breaks down lower in the digestive tract to prevent reflux. A 10% solution of peppermint oil in alcohol or olive oil may be applied to infected skin every 15 and 30 minutes with a health care provider's approval.