Oil of Oregano

What is "Oil of Oregano" and how is it used? Why is so hard to find in this country? Does it have any side effects?

Oil of oregano is the distilled essential oil of the leaves and tops of the Greek oregano plant. Recently a naturopath, Dr Cass Ingram, has been extolling the medicinal virtues of oregano oil at natural health shows and in books. Dr. Ingram's book, "The Cure is in the Cupboard: How to Use Oregano for Better Health", is available from Richters.
We usually think of oregano as a culinary herb, especially in Mediteranean cuisine, so it comes as a surprise to many people that oregano is also a medicinal herb.
Dr. Ingram writes that oregano oil is a potent medicinal product, with use against everything from chronic pain to viral pneumonia. In the book, Dr. Ingram cites research and clinical experience that supports the case for oregano as a medicinal herb.
Oregano oil is available from Richters, in 4 mL and 25 mL sizes.