The functional activity of the sphincter of Oddi complex has been examined by ceruletide manometry in patients undergoing cholecystectomy with a normal peroperative cholangiogram. In Group I (n = 14), which included patients with previous acute cholecystitis/biliary colic, the sphincter activity appeared to be normal and responded to intravenous ceruletide by a marked relaxation with a significant fall in both the infusion and postinfusion pressures. In patients undergoing cholecystectomy for gallstone-associated pancreatitis (n = 8), the sphincter exhibited manometric features of hypotonia with low infusion and postinfusion pressures which were not significantly altered by intravenous ceruletide.