Gary Michael Null is an American talk radio host and author who advocates for alternative medicine and naturopathy and who produces a line of dietary supplements.
His views on health and nutrition are at odds with scientific consensus; Stephen Barrett, co-founder of the National Council Against Health Fraud, described Null as "one of the nation's leading promoters of dubious treatment for serious disease".
On his radio show, and in books and self-produced movies, Null criticizes the medical community, promotes a range of alternative cancer treatments, denies that HIV causes AIDS, and promotes dietary supplements which he produces.
In 2010, Null reported that he and six other consumers had been hospitalized from vitamin D poisoning, after ingesting a nutritional supplement carrying his name and endorsement. Null sued a contractor involved in producing the product, alleging that each contained more than 1,000 times the dose of vitamin D reported on the label.