born 1624, Wynford Eagle, Dorset, Eng.
died Dec. 29, 1689, London
British physician.
His Observationes medicae (1676) was a standard textbook for two centuries, noted for its detailed observations and the accuracy of its records. His treatise on gout (1683) is considered his masterpiece. He was among the first to explain the nature of hysteria and St. Vitus dance (Sydenham chorea) and to use iron to treat iron-deficiency anemia. Sydenham also named scarlet fever and differentiated it from measles, first used laudanum (a solution of opium in alcohol) as a medication, and helped popularize the use of quinine for malaria.