This article explores why cancer patients use complementary and alternative medicine (CAM), why CAM use should be of interest to physicians who treat cancer patients, and how physicians may appropriately support their patients' quest for comfort, quality of life, and healing. We use the term "CAM" to refer to substances and practices that have been available primarily outside of the American medical mainstream, that have sources other than medical doctors and allied health care providers, and that are not commonly recommended by medical doctors as treatments for a given condition. Alternative treatments are those used instead of conventional medicine; complementary treatments are those used in addition to conventional medicine.