Rudolf Magnus (2 September 1873, Brunswick – 25 July 1927, Pontresina) was a German pharmacologist and physiologist. He studied medicine, specialising in pharmacology, in Heidelberg, where he became associate professor of pharmacology in 1904. In 1908 he became the first professor of pharmacology in Utrecht, where he spent the rest of his working life. Magnus had five children, Karl (1903-1989) lung specialist; Margarete (Gretl)(1905-1968)who worked as his secretary and translator; Dorothea who died aged 11; Erica (1909-1991) architect; and Otto (1913-2014) neurologist.