We studied effects of urokinase (Uronase) on the transfer of an oral anticancer agent, 1-hexylcarbamoyl-5-fluorouracil (HCFU) into blood, bile and pancreatic juice in 5 patients in whom pancreaticoduodenectomy has been performed for cancer of the periampullary region, and who had been simultaneously provided with drainage of the bile duct and pancreatic duct. Following oral administration of 500 mg of HCFU, HCFU and 5-FU concentrations in blood reached a peak at 2 hours, those in bile at 4 hours, and those in pancreatic juice at 4 to 6 hours. The administration of 24,000 IU of urokinase in combination with HCFU resulted in increased HCFU and 5-FU concentrations in blood, bile and pancreatic juice--the HCFU concentration in bile increased to 3 times and that in pancreatic juice, to about 5 times the level in the some counterparts in urokinase--untreated patients. These changes seemed to have resulted from the acceleration by urokinase of distribution of the anticancer agent into the organs.