The operative diagnosis of colonic ischaemia in association with acute necrotizing pancreatitis (ANP) may be difficult in the absence of unequivocal transmural necrosis or perforation. We introduced in May 1988 a new policy whereby, when colonic viability was dubious, resection was avoided and a diverting loop ileostopy (DLI) was performed. If necrosectomy led to extensive mobilization of the splenic flexure with a capillary drainage system placed in close contact, a DLI was again performed. Colectomy was only performed for unequivocal transmural necrosis. Among 30 patients operated on for ANP, 12 underwent DLI. This policy allowed us to spare potentially ischaemic colons. No secondary colonic complication occurred and there was no rise in the mortality rate. Among patients whose colon was kept in circuit there were bouts of bowel distension and unexplained bacteriemia ultimately leading to death from multiorgan failure. When colonic viability is dubious and when drainage is brought up in close contact with the bowel wall DLI might allow colonic resection to be avoided. In our experience DLI also seemed to prevent secondary colonic complications.