Acute perineal gangrene due to anaerobic Gram negative bacilli or streptococci rapidly leads to tissue necrosis and death in 50% of the cases despite progress in intensive care. Emergency treatment requires adapted antibiotics, hyperbaric oxygen therapy and repeated surgery. Factors of poor prognosis include age over 60 years, lomboabdominal or crural extension, septic shock, positive blood cultures and lack of fecal derivation. Surgery is performed under general anaesthesia since loco-regional anaesthesia is contraindicated during the septic phase. Repeated operations are needed to make large incisions, evacuate pus, search for foreign bodies and resect damaged tissue in order to expose all the infected areas to air and hyperbaric oxygen. A colostomy must be performed in order to avoid fistulization and contamination of the infected areas. An indwelling urine catheter is usually sufficient although a suprapubic catheter may be needed at the risk of further extension of the gangrene. Surgical treatment is associated with intensive care and hyperbaric oxygen therapy. Three effective antibiotics are recommended. Using this aggressive surgical protocol, we have been able to reduce mortality to 20% in patients under 60 years of age.