Functional medicine is the name of a branch of alternative medicine that includes a number of both unproven and discredited healing methods and treatments.
Its practitioners claim that it focuses on so-called ‘deep or root causes’ of disease that are based on the interactions of the gastrointestinal, endocrine and immune system with the external environment. Based on these interactions (that occur in unspecified ways) they develop individual treatment plans for patients. It is regarded as a melding and re-branding of alternative and complementary medical techniques with none of their grounds for efficacy.
Described as quackery and pseudoscience by the medical scientific community its vaguely defined and unnecessary testing practices have been ruled ineligible for teaching by the American Academy of Family Physicians because of concerns about the unscientific nature of its practices and evidence that some of them may be harmful.