In 13 patients with advanced peritonitis (postoperative suture line breakdown in eight and spontaneous intestinal perforation in five) treatment consisted of widely opening the peritoneal cavity and exposing the contaminated viscera. Eight of the patients underwent diverting enterostomy, and the remaining five underwent an additional drainage procedure to evacuate a residual collection. Clinical improvements were observed in all except one who died without favorable response. Some of the clinical manifestations indicative of organ failures subsided in nine of the ten patients. In five patients peritonitis subsided completely, whereas in another seven it was localized, leaving a fistula; in five of them reoperative closure of the abdominal wall and fistula was performed with one operative death. One patient developed a new enteric fistula from the previous anastomotic site that had been exposed after opening the abdominal wall. There was no intestinal obstruction or inreducible bowel pretrusion during the course of treatment. It was concluded that the open peritoneal drainage procedure, combined, if necessary, with diverting enterostomy, should be considered for advanced peritonitis causing grave systemic complications.