From 1988 to 1992, 50 cases of perineal gangrene were treated with a therapeutic protocol combining: a) repeated extensive excisions, b) hyperbaric oxygen therapy, even before surgery if this was possible, and c) intensive care. The mortality rate was 24% (12/50). It was even higher in patients admitted more than 6 hours after diagnosis. The average stay in hospital was of 20 (+/- 2) days. Four patients presented with residual signs. Twenty-eight (56%) had had colostomy for lesions originating in the rectum or threatening the anal margin; 9 of these patients died, while gastrointestinal continuity was restored in another 17 cases. There were three predictive factors of survival in this series: a) early diagnosis and treatment, b) severity index on admission, c) some associations of bacteria.