Call it "alternative," "complementary," "integrative" or "holistic" medicine. Whatever name you choose, such nontraditional therapeutic practices as acupuncture, homeopathy and yoga have become increasingly prominent--and provocative--parts of the U.S. medical landscape. An estimated 50% of all Americans turn to some type of alternative therapy; three-quarters of U.S. medical schools offer courses in the subject; and even flinty-eyed health insurers are starting to pay for visits to your local herbalist or naturopath.
This shift reflects a growing public yearning for gentler, less invasive forms of healing. But unconventional potions and practices afford rich opportunities for quackery. Health-food magazines and websites are filled...