Abstract198Au-gold colloid liver scans and75Se-selenomethionine pancreas scans in 72 patients with extrahepatic obstructive jaundice were assessed by blind marking. They were compared with liver and pancreas scans from 20 control patients and liver scans from 33 patients with diffuse liver disease. 56 per cent of the liver scans in extrahepatic obstructive jaundice showed a filling defect in the hilar region of the liver. This was most frequently seen in the most deeply jaundiced patients, and was reported in 80 per cent of patients with a serum bilirubin greater than 15 mg/100 ml. The liver scan alone cannot distinguish between different forms of extrahepatic obstructive jaundice although severe loss of left lobe uptake appeared to favour a diagnosis of carcinoma of the bile or hepatic ducts.A normal pancreas scan virtually excludes a pancreatic carcinoma as the cause of obstructive jaundice. A pancreas scan showing severely reduced uptake suggests a carcinoma of the pancreas or of the lower end of the common bile duct.