Perforation of the colon is a rather uncommon complication of ulcerative colitis. Bargen,1 in a series of 693 cases of ulcerative colitis with two hundred and sixty-eight complications of various types, found perforation fifth in order of frequency. Bargen and Jacobs2 reported twenty-two perforations (3.4 per cent) in 647 cases. Jackman, Bargen and Helmholz3 found two perforations in 95 cases of ulcerative colitis in children (2 per cent) and sixteen in the total group of 871 cases (1.1 per cent). As nearly as can be judged from the literature, free perforation of the colon with generalized peritonitis has hitherto been a fatal occurrence. Chronic perforation with abscess formation, on the other hand, is not infrequently followed by recovery. The purpose of this paper is to report 3 cases of what was considered to be perforation of the colon with generalized peritonitis successfully treated with sulfonamide drugs and