Endoscopic cholangiopancreatography in hepatic clonorchiasis--a follow-up study. Cholangiographic changes of the biliary system in 16 patients with proven hepatic clonorchiasis, diagnosed by positive stool or bile ova isolates, were studied. All patients presented with epigastric pain. Other symptoms included jaundice in 31% (5 of 16) and fever in 12.5% (2 of 16). Praziquantel given at 25 mg/kg for three doses in 1 day were administered. Three consecutive stool tests were performed 3 months after treatment and were negative in 87.5% (14 of 16). ERCP studies were repeated at a mean interval of 31.6 months (range, 8 to 69 months). Measurements of the bile ducts on retrograde cholangiograms before and after treatment were compared using the paired Student's t test. Filling defects and blunting of the terminal bile ducts seen on the initial cholangiogram, interpreted as the presence of adult worms, disappeared after treatment. However, there was no significant change between pre- and post-treatment measurement of bile duct caliber. Bile duct dilation, irregularities, and ductal proliferation persisted despite eradication of the parasite. 