I found a great article on Oil of Oregano. Here is some of what it said:
Oil of oregano is a completely natural substance derived from wild oregano species. The plant grows in remote mountainous regions free of pollution. Only the leaves of the flowering plant are used. They are picked precisely when the plant is highest in essential oil. Being wild, it is grown chemical-free and the oil is extracted via a completely natural process - no chemicals or solvents are used. The oil is the source of virtually all of the plant's active ingredients.
Oil of oregano is a potent germ killer. Jean Valnet, in his book The "Practice of Aromatherapy", describes how oil of oregano superceded anti-inflammatory drugs in reversing pain and inflammation and is nearly as powerful as morphine as a painkiller. The oil also possesses significant antioxidant power. Furthermore, it stimulates the flow of bile, which greatly aids digestion.
Oregano oil (Origanum vulgare) is well known in the Mediterranean world (Greece and Crete) for its ability to slow down food spoilage through its anti-bacterial, anti-fungal, anti-parasitic and anti-oxidant activity. The related herbs thyme and marjoram sold in most North American supermarkets, are labeled incorrectly as oregano and possess little of wild oregano's miraculous healing properties.
HOW IT WORKS
Isomeric phenols (primarily carvacrol) in oregano oil in dilutions as low as 1/50,000 destroys Candida albicans, the Aspergillus mold, Staphylococcus, Campylobacter, Klebsiella, E.coli, Giardia, Pseudomonas, and Proteus. Another phenol constituent, thymol, boosts the immune system. These compounds also act as free radical scavengers (shield against toxins) thus preventing further tissue damage while encouraging healing.
Oil of oregano is antiviral, antibacterial, antifungal, and antiparasitic. It also has strong antioxidant and anti-inflammatory effects and is an ideal product to use for people who suffer from CFS and/or fibromyalgia. This is not regular oregano, but a wild form (wild mountain oregano, vulgare species) of the spice, which has, until recently, not been available in Canada. Do not use a substitute or oregano from a grocery store because it will have no effect. oil of oregano natural herbal supplement offers a variety of remedies.
There is a lot more to read about, so follow this link for more.