The pathways of enzyme transfer from the pancreas into the systemic circulation were analyzed in sodium taurocholate-induced acute hemorrhagic pancreatitis in the rat by estimating lipase concentrations in blood, lymph and ascites. During the first few hours of pancreatitis high enzyme levels were observed in thoracic duct lymph. However, cannulation of the thoracic duct did not prevent a significant increase in the lipase concentration in peripheral blood. The portal vein lipase concentration was found to exceed the peripheral values by approximately 10%. Extremely high concentrations of lipase were measured in the ascites collected during pancreatitis. When the ascites was transferred to the peritoneal space of healthy rats, a significant increase in the lipase concentration in peripheral blood was measured. This increase could not be prevented by transection of the parasternal lymphatics. It was concluded that the hematogenous rather than the lymphatic transport of lipase from the pancreas and the peritoneal surface is the most important pathway. In this respect, this study does not support thoracic duct drainage but advocates peritoneal lavage as a logical therapeutic measure to reduce the concentration of circulating toxic substances from the pancreas in acute pancreatitis.