Of 554 cirrhotics autopsied during 1975-1993, 69 had had peritoneovenous shunts. Generalized peritoneal fibrosis with cocoon formation was found in 26 (38%) of those with shunts but in only one of 485 without shunts (P = 0.00002). In 14/26 the fibrosis was asymptomatic, an incidental autopsy finding. Intestinal obstruction in 12/26 (46%), the only symptomatic manifestation, was fatal in five. The etiology of peritoneal fibrosis in shunted patients is unknown. The 26 patients with fibrosis had more prior abdominal operations, complicated abdominal wall hernias, and active biliary tract inflammations; the features differentiated them from the 43 patients without fibrosis. Scores in a 'peritoneal complication index,' that considered multiple risks in the same patients, were significantly higher in those with fibrosis. In addition to these peritoneal injuries or inflammations, the faster ascitic fluid circulation in shunted patients may have increased deposition of fibrin upon the peritoneum. Fibrogenic cytokines, thus spread throughout the abdomen from local sites, may have converted fibrinous adhesions to generalized peritoneal fibrosis.