Octreotide (SMS 201-995) is a long-acting somatostatin analogue that inhibits both basal and secretin-cholecystokinin-stimulated pancreatic secretion. This study assesses the effect of this compound on pancreatic secretion induced by ordinary meals. Three patients with stable secretion of pure pancreatic juice from high output pancreatic fistula were studied. In all three, meal ingestion caused a marked and prolonged increase in pancreatic juice flow, and in bicarbonate and protein output. The subcutaneous injection of 50 micrograms octreotide before meals almost totally prevented (by about 90%) this increase. The inhibitory effect of octreotide on postprandial pancreatic secretion appeared soon, and persisted for the duration of the study period (8 h).