Oil of oregano may help fight bacterial and fungal infections, remove parasites and treat sore throats. While some research indicates that oil of oregano is effective at killing intestinal parasites, there is insufficient scientific evidence to support the majority of the product's claims, as of 2015.
Naturopathic medical practitioners use oil of oregano to treat health issues including asthma, bronchitis, heartburn, menstrual cramps and athlete's foot. Some people also use it as an insect repellent or a treatment for insect bites. Oil of oregano contains some chemical compounds that may aid in reducing respiratory spasms as well as increasing bile flow to improve digestion.
Some clinical studies have indicated that regular ingestion of oregano oil for a prolonged period of time may help convert "bad" cholesterol into "good" cholesterol in patients with pre-existing high cholesterol. Oregano oil taken orally over a period of six weeks kills the intestinal parasites Blastocystis hominis, Entamoeba hartmanni and Endolimax nana.
Oregano oil is generally safe for consumption when taken occasionally. In medicinal amounts it may cause minor stomach or skin irritation. Pregnant and breast-feeding women should consult a doctor before taking oil of oregano in medicinal amounts, as there may be a higher risk of side effects.