Previously, the authors documented that extrahepatic biliary obstruction promotes the systemic translocation of bacteria from the intestine to visceral tissues. The current experiments were performed to determine whether it was the absence of intestinal bile or the presence of biliary obstruction that promoted bacterial translocation. Four groups of rats were studied: 1) nonoperated controls (n = 20), sham common bile duct-ligated (n = 22), common bile duct-ligated (n = 25), and common bile duct-diverted (choledochovesical bypass) (n = 23). The sham-ligated group underwent laparotomy and manipulation of the portal region; whereas the ligated group had their common bile ducts ligated, while the choledochovesical group had a silastic tube placed from the common bile duct to the bladder. Seven days later, at death, the incidence of bacterial translocation was higher in the groups of rats subjected to common bile duct ligation (41%) or diversion (32%) than in the control (3%) or sham-ligated (5%) groups (P less than 0.05). Histologic sections of ileums of ligated and diverted animals both showed subepithelial edema. These findings suggest that it is primarily the absence of bile in the intestine that promotes mucosal injury and bacterial translocation and not biliary obstruction.