Alfred Blalock (April 5, 1899 – September 15, 1964) was a 20th-century American surgeon most noted for his research on the medical condition of shock as well as Tetralogy of Fallot— commonly known as Blue baby syndrome. He developed the Blalock-Thomas-Taussig Shunt, a surgical procedure he developed together with surgical technician Vivien Thomas and pediatric cardiologist Helen Taussig to relieve the cyanosis from Tetralogy of Fallot.