Gerhard Domagk (gĕr´härt dō´mäk), 1895–1964, German chemist and pathologist. A teacher successively at the universities of Greifswald and Münster, he became (1927) director of research at the I. G. Farbenindustrie laboratory at Wuppertal. Because of a Nazi decree he was obliged to decline the 1939 Nobel Prize in Physiology or Medicine. In 1947 he received a gold medal in lieu of the prize money. The award was made for his discovery of the efficacy of prontosil, the forerunner of the sulfa drugs, in treating streptococcal infections.