Infected necrotizing pancreatitis is the most fulminant variety of this disease. Colonic involvement and retroperitoneal fasciitis are particularly lethal. The reported mortality is up to 50%. The purpose of this study is to review our combined experience at the Princess Alexandra Hospital and the Royal Brisbane Hospital, Brisbane, to determine whether patient survival was related to a particular etiology, treatment, or complication. all patients treated since 1986 with infected pancreatitis who required surgical necrosectomy and then ventilation in the intensive care unit (ICU) were studied. There were 48 patients so managed. The median age of survivors was 52 years, and for those who died it was 64 years (p = 0.001). The etiology was gallstones in 22 and alcoholism in 12. Of the alcoholics, 11 survived and 1 died. Of the patients with gallstones, 13 survived and 9 died. There was an overall mortality of 31%. Survivors were in hospital for a median of 73 days, whereas deaths occurred after a median of 35 days (p = 0.04). Seven patients underwent hemofiltration; five survived, and two died. N-Acetylcysteine has been used in four patients, of whom three survived and one died. The abdomen was left open in 38 patients and kept closed in 10. Although Ranson's criteria at admission to the ICU did not predict survival, ti was found that the median APACHE II score in survivors was significantly lower than in those who died (p = 0.025). However the need for colectomy or the finding of retroperitoneal fasciitis in seven patients caused a significantly higher mortality, which was not predicted by Ranson's criteria or APACHE II scores (p = 0.007). Death was due to overwhelming sepsis in most cases, although 47% of patients who died had also suffered major bleeding or fistulas. Nonparametric, box plot analysis shows the following trends: (1) Alcohol was not the most common cause of necrotizing pancreatitis, nor did it carry the highest mortality. (2) Tissue adjacent to the pancreas progressively necrosed over days or weeks. (3) Low initial APACHE II scores were frequently found in patients who ultimately died with colonic necrosis and retroperitoneal fasciitis. (4) Survivors tended to be treated by open laparostomy sooner, have longer periods in hospital, and be significantly younger. In conclusion, patients do best with early, open, repeated surgical debridement of the retroperitoneum for what appears to be an ongoing process.