For example, the widely referenced descriptive definition of complementary and alternative medicine devised by the US National Center for Complementary and Integrative Health (NCCIH) of the National Institutes of Health (NIH), states that it is "a group of diverse medical and health care systems, practices, and products that are not generally considered part of conventional medicine".
Eksempelvis siger den bredt citerede deskriptive definition af komplementær og alternativ medicin udarbejdet af US National Center for Complementary and Intergrative Health (NCCIH) fra National Institutes of Health (NIH), at det er "en gruppe af forskelligartede behandlingsformer og produkter, der ikke generelt anses som en del af konventionel medicin".