Functional medicine is a health-care practice that treats the underlying cause of disease and illness, usually doing so as naturally as possible and emphasizing dietary and lifestyle changes, nutritional supplements and herbal medicines. Lab testing and intakes are used to guide treatment and determine what an underlying cause of illness or malfunction might be. Functional medicine considers client accessibility to the health practitioner as a necessity through a health building program as client needs do change over time. The practitioner needs to know how a client is responding to recommendations and make adjustments accordingly.