Despite the proposal that somatostatin or its stable analogue, octreotide (SMS-201,995), may exert an ameliorating effect on acute pancreatitis, data concerning its beneficial effect in this situation are conflicting. This study examines the effects of octreotide on acute pancreatitis, resulting from the retrograde injection of a bile salt (taurocholate) plus saturating trypsin into the common bile-pancreatic duct of the rat. Octreotide given before the induction of pancreatitis significantly reduced the levels of serum amylase and lipase, ascites amylase concentration, degree of leukocyte infiltration, and focal areas of pancreatic tissue necrosis. In contrast, administration of octreotide as soon as 5 min following induction had no demonstrable ameliorating effects on the pancreatitis. These results indicate that octreotide may have application to prophylaxis of acute pancreatitis in cases where bile salts may play a role in pathogenesis, but may not be beneficial in established acute pancreatitis.