Dietary supplements are used by about 75% of Americans. They are the most common therapies included among integrative medicine and health (IMH) and complementary and alternative medicine (CAM), which include healing approaches and therapies that historically have not been included in conventional, mainstream Western medicine. Dietary supplements include medicinal herbs and nutraceuticals (products derived from food sources that claim to provide health benefits). Because the use of dietary supplements is widespread, the United States government passed the Dietary Supplement Health and Education Act (DSHEA) in 1994. It defines a dietary supplement as any product (besides tobacco) that contains a vitamin, mineral, herb or other plant product, or amino acid and that is intended as a supplement to the normal diet. Certain hormones, such as dehydroepiandrosterone (DHEA) and melatonin, also are considered dietary supplements.