Mehmet Cengiz Öz (Turkish: [mehˈmet dʒeɲˈɟiz œz]; born June 11, 1960), known professionally as Dr. Oz, is a Turkish-American television personality, cardiothoracic surgeon, Columbia University professor, pseudoscience promoter, journalist, and author. In 2003, Oprah Winfrey was the first guest on the Discovery Channel series Second Opinion with Dr. Oz, and, since 2004, Oz became a regular guest on The Oprah Winfrey Show, making more than sixty appearances In 2009, The Dr. Oz Show, a daily television program focusing on medical issues and personal health, was launched by Winfrey's Harpo Productions and Sony Pictures Television.
He is a proponent of alternative medicine, and has been criticized by physicians, government officials, and publications, including Popular Science and The New Yorker, for endorsing unproven products and non-scientific advice. The British Medical Journal published a study that found more than half of the recommendations on medical talk series like The Dr. Oz Show had either no evidence or contradicted medical research. Donald Trump's appointment of Oz to the Council on Sports, Fitness, and Nutrition was criticized as an example of choosing "pundits over experts".