Now, these are truly diverse areas and we aggregate them for work purposes at the National Center for Complementary and Alternative Medicine into five major domains. These are biologically based systems, including special diets and thousands of different kinds of herbal remedies. These include manipulative and body-based systems, such as massage, chiropractic, and osteopathic manipulation.

Energy therapies, involving things that are truly based on energies with electromagnetic radiation, such as magnets and electro-acupuncture, and things that are purporting to work through energy, such as reiki and qi gong and other forms of Asian health care practices.

There are mind-body approaches of which many are within the field of CAM, including yoga and meditation. And there are whole systems that exist as parallel health care universes we call alternative medical systems. Some of which are ancient -- ayurvedic medicine from India, traditional Chinese medicine -- as well as things in the past two centuries that evolved in Europe and the United States, such as naturopathic medicine and homeopathy.