Octreotide (Sandostatin 201-995) has an inhibitory effect on gastric, intestinal, and pancreatic secretions and hepatic and splachnic blood flow. We examined the effects of octreotide on bile flow and bile components in 10 patients with T-tube choledochostomy. A Fogarty balloon catheter was inserted distal to the T-tube of these patients for measurement of bile flow and bile components. Bile samples were obtained to analyze bile acid, phospholipid, lipoprotein, and cholesterol, and bile flow measurements were performed every 15 min for a period of 90 min before study and after normal saline and octreotide administrations. While octreotide had an inhibitory effect on bile flow, the concentrations of bile acid, phospholipid, and lipoprotein in bile were increased with octreotide.