Functional medicine is a form of alternative medicine which proponents say focuses on interactions between the environment and the gastrointestinal, endocrine, and immune systems. Practitioners develop individual treatment plans for people they treat. Functional medicine encompasses a number of unproven and disproven methods and treatments, and has been criticized for being pseudoscientific.
The discipline of functional medicine is vaguely defined by its proponents. Oncologist David Gorski has written that the vagueness is a deliberate tactic which facilitates the discipline’s promotion, but that in general it centers on unnecessary and expensive testing procedures performed in the name of “holistic” health care.
Proponents of functional medicine oppose established medical knowledge and reject its models, instead adopting a model of disease based on the notion of “antecedents”, “triggers”, and “mediators”. These are meant to correspond to the underlying causes, the immediate causes, and the particular characteristics of a person’s illness respectively. A functional medicine practitioner will devise a “matrix” from these things which acts as a basis for treatment.