Using a percutaneous transhepatic cholangioscopy (PTCS) catheter, sphincter of Oddi motility was measured in a patient with papillary stenosis secondary to bile duct stones. Prior to sphincterotomy, intramuscular injection of 20 micrograms caerulein did not inhibit pathological contraction waves of the sphincter of Oddi or relieve abdominal pain. Endoscopic sphincterotomy of the lower segment of the sphincter of Oddi resulted in recovery of the normal response to caerulein, i.e. relaxation of the sphincter of Oddi. This observation indicates that the pathological contraction and lack of relaxation to cholecystokinin in a patient with papillary stenosis is due to high common bile duct pressure. The measurement of motility of sphincter of Oddi via the PTCS route is useful in diagnosing motor disorders in the sphincter of Oddi and is helpful in deciding to perform endoscopic sphincterotomy.