Charon Robin Ganellin FRS (25 January 1934 – ) is a British medicinal chemist, and Emeritus Smith Kline and French Professor of Medicinal Chemistry, at University College London. He has contributed much to the field of drug discovery and development. His most outstanding achievement was the discovery of cimetidine, a drug used to combat stomach ulcers, when he was working at Smith Kline and French. He has received many awards and much recognition for his scientific pursuits over the years. He now lives near London and is a professor at University College London.