Joseph Michael Mercola (born July 8, 1954) is an American alternative medicine proponent, osteopathic physician, and Internet business personality. He markets largely unproven dietary supplements and medical devices. On his website, Mercola and colleagues advocate unproven and pseudoscientific alternative health notions including homeopathy and opposition to vaccination. These positions have received persistent criticism. 

Mercola is a member of several alternative medicine organizations as well as the political advocacy group Association of American Physicians and Surgeons, which promotes scientifically discredited views about medicine and disease. He is the author of two books.