Acute hemorrhagic pancreatitis was produced in the dog by the closed-loop technique. The presence of bile in the closed loop was not needed to induce the pancreatitis; however, its presence influenced the appearance of the disease. Bile in the closed loop caused an earlier appearance of pancreatic acinar tissue disruption and elevated serum lipase, alkaline phosphatase, and lactic dehydrogenase levels; there were increased fluid volumes in the closed loop and higher amylase concentrations in the peritoneal fluid.