The National Center for Complementary and Alternative Medicine at the National Institute of Health in the United States, defines them as a group of systems for medical attention, curing practices and products herbs, minerals, vitamins, etc. that are not considered by the "western, allopathic" medicine or biomedical National Center for Complementary and Alternative Medicine, 2008.
El Centro Nacional de Medicinas Alternativas y Complementarias de los Institutos Nacionales de Salud de EE.UU., las define como un conjunto de sistemas de atención médica, prácticas de curación y productos hierbas, minerales, vitaminas, etc. que no son considerados por la medicina "occidental, alopática" o biomédica National Center for Complementary and Alternative Medicine, 2008.