Essential oils are an excellent way to concentrate the benefits of therapeutic herbs and essential oils for nearly all herbs are available. One of the most beneficial is peppermint oil, which is extracted by steam distillation from the peppermint, or mentha piperita, plant. The primary component of peppermint oil is menthol which provides the familiar flavor and cooling sensation, but peppermint oil also contains various minerals, vitamin A, vitamin C, and fatty acids.
Peppermint oil can be used to address a wide range of health ailments, both internally and externally. It’s an ingredient in many lotions and ointments. Topical application can relieve aches and pains, benefit the skin, and a few drops on the wrist is even a common recommendation to relieve a headache. Peppermint oil is commonly used in aromatherapy, many people will inhale the vapors to sooth their respiratory tract and lungs. Peppermint oil also has internal use to combat indigestion and harmful organisms.
Peppermint Oil and Irritable Bowel Syndrome (IBS)
It’s no secret that peppermint oil can relax the smooth muscles of the respiratory tract, but did you know it can do the same to the smooth muscles in your GI tract?  There are many OTC remedies for symptoms of IBS and many of them contain peppermint oil, with good reason. The Department of Complementary Medicine at the University of Exeter in the UK examined over a dozen studies that collectively indicated peppermint oil was effective at relieving IBS symptoms.  Much evidence suggests that, when compared to available drugs for IBS, peppermint oil may be the best choice to alleviate symptoms and improve quality of life for IBS patients. 
Peppermint Oil and Harmful Organisms
Many essential oils are known to be resistant to most harmful organisms. Peppermint oil is no exception and its menthol content has even been found to be effective against mosquitos and head lice.  
Peppermint Oil and Bacteria
Peppermint oil is toxic to bacteria by way of chemicals which have antioxidant potential.  When evaluated for resistance to bacteria, peppermint oil and its components: camphor, menthol, and carvacrol have been found to be effective; notably, carvacrol has the highest activity.   Other studies have evaluated and confirmed the antioxidant and potential of peppermint oil and a Syrian study even found peppermint oil to be effective against a strain of microbes known to target livestock.  
Peppermint Oil and Fungus
The general resistance of essential oils to fungus is well documented and peppermint oil is no exception. Indian and Iranian researchers have shown that peppermint oil holds potential for managing fungal infections, including candida.   Their assertion was backed up by the Institute for Biological Research in Serbia where researchers observed fungicide behavior from peppermint oil.  The Tehran University of Medical Sciences in Iran also, after comprehensive review, concluded that menthol is resistant to fungus, including candida.  Similarily, Brazil’s State University of Campinas found essential oils of three different peppermint varieties to be anti-candida. 
One of the most positive discoveries about peppermint oil was found by the US Air Force 375th Medical Group Family Medicine Residency Program who conducted a study of 18 participants suffering from fungal nail infection. During the 48 week study, the participants applied a vapor rub that contained menthol to their nails. All 18 reported positive changes to their nail appearance by the end of the study. 
- Dr. Edward F. Group III, DC, ND, DACBN, DCBCN, DABFM
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