Paradoxically, the less evidence that exists to support the use of of a treatment, the more passionate its supporters seem to be. I learned this early in my career as a pharmacist. One pharmacy I worked at did a steady business in essential oils. And king of the oils was oil of oregano. Not only were there several different brands of the basic oil, they were different forms, including capsules, creams and even nasal sprays. Not aware of any therapeutic benefits, I would ask customers what they were using it for. I rarely heard the same condition described: skin infections, athlete’s foot, head lice, colds, sore throats, “parasites”, “yeasts”, diabetes, allergies and ringworm were apparently no match against the judicious use of oregano oil. Intrigued, I took a closer look.
Long before our scientific understanding of bacteria and antimicrobials, infected wounds were packed with different products in an attempt to minimize the odour, and hopefully speed healing. It’s likely that someone happened upon a fragrant herb and discovered that it seemed to help treat wounds (or at least, cover some of the smell). Given there have been some amazing drugs with powerful effects that have emerged from natural products, it’s certainly plausible that oil of oregano could have biological and therapeutic effects. Oregano (Origanum vulgare) leaves contain a wide variety of chemical compounds, including leanolic acids, ursolic acids, and phenolic glycosides. Phenolic compounds make up to 71% of the oil. Carvacrol, thymol, cymene, and terpinine and are found in oregano leaves and do appear to have biological effects. It’s these chemicals that are proposed to be the parts with beneficial effects.
The claims made by one manufacturer are unambiguous:
Oreganol P73 is the most powerful germ killer with scientifically proven results against almost every virus, bacteria, parasite, and fungi. The complexity of the phytochemical matrix in Oreganol P73 possesses a broad spectrum of antimicrobial properties that are safe for prolonged use. The oil can be used topically and internally. Oreganol P73 is the medicine chest in a bottle, especially since it is proven never to harm the internal organs, even when used daily for health maintenance.
So if we accept the manufacturer’s claims at face value, there should be evidence demonstrating oregano oil is both safe and effective when used internally and externally. There is apparently also adequate long-term safety data to demonstrate that it can be safely used on a daily basis.