Intravenous cholangiography was carried out in 80 anicteric patients using ioglycamide (Biligram). Twenty patients were given a 30 ml ampoule of 35% ioglycamide as a slow hand injection over ten minutes; the remainder were given ioglycamide by one hour slow drip infusion at a rate of 2, 3, or 4 mg per kg body weight per minute. The radiological opacification of the bile duct was then assessed independently by two radiologists. There was a statistically significant difference between the bile duct opacification found in patients given either 3 or 4 mg/kg/min of ioglycamide for one hour compared with those given ioglycamide either by ten minute injection or by 2 mg/kg/min drip infusion.