Functional medicine (FM) is a form of alternative medicine that encompasses a number of unproven and disproven methods and treatments. It has been described as pseudoscience, quackery, and at its essence a rebranding of complementary and alternative medicine. In the United States, FM practices have been ruled ineligible for course credits by the American Academy of Family Physicians because of concerns they may be harmful. Functional medicine was created by Jeffrey Bland, who founded The Institute for Functional Medicine (IFM) in the early 1990s as part of one of his companies, HealthComm.
https://en.wikipedia.org/wiki/Functional_medicine