The effect of furosemide on biliary excretion of ioglycamide and bile flow during experimental cholangiography was studied in cholecystectomized and anaesthetized dogs equipped with a Thomas cannula through which the common bile duct could be cannulated. Ioglycamide infusion was started one hour after cannulation of the common bile duct, the infusion rate being 4 micromol/min/kg. Two hours later, 2 mg/kg furosemide was injected intravenously. After furosemide administration biliary ioglycamide concentration and bile flow remained the same as before the furosemide administration. Our evidence suggests that furosemide has no effect on the biliary excretion of ioglycamide or bile flow during ioglycamide cholangiography on dogs.