Recent experience with patients with bile ascites and bile peritonitis prompted a review of other case histories in the medical literature of these conditions. The clinical courses of 24 patients with bile ascites and 34 with bile peritonitis were reviewed. Bile ascites occurred most often as a postoperative complication of biliary tract operations and also occasionally after trauma. Clinical signs were minimal except for abdominal distention, and operations were delayed for an average of 30 days. Peritoneal fluid was sterile in the 11 patients studied. In contrast, bile peritonitis occurred most commonly after spontaneous perforation of the gallbladder or hepatic ducts but also after trauma. All patients had severe signs of peritoneal irritation, and operation was performed earlier, at a mean of 4 days after onset of symptoms. Of 11 patients with specimens of their peritoneal fluid cultured, 6 had sterile fluid and 5 had bacteria. Although both bile salt concentration and bacteria have been implicated in the development of bile peritonitis rather than bile ascites, our understanding of the mechanisms involved is still incomplete.