Conclusions and summary We have demonstrated that ligation of the common bile duct in the rat is followed within a few days by necrotizing hemorrhagic pancreatitis, considerable edema of the gland, fat necrosis, and often relatively large amounts of yellow ascitic fluid. The mixture of pancreatic and biliary secretion accumulated in the obstructed common duct as well as the ascitic fluid contained little or no trypsinogen and no free trypsin. Values of enzyme concentrations in pancreatic secretion of the normal rat are reported.