A 47-year-old woman with stones in the gall-bladder suddenly developed severe upper abdominal pain. Cholesterol concentration was elevated, as were amylase (555 U/l) and lipase (408 U/l) concentrations, suggesting biliary pancreatitis. Endoscopic retrograde cholangiography demonstrated a cyst, about 10 cm in diameter, in the left lobe of the liver, connected to the biliary tract system. Ultrasonography and computed tomography additionally showed a smaller cyst in the right lobe. Infection with Echinococcus granulosus was proven microbiologically on bile (demonstration of hooklets and protoscolices) as well as serologically. Transpapillary cholangioscopy demonstrated daughter cysts within the echinococcal cyst. The main cyst was rinsed with 20% NaCl for 10 days via a nasocystic catheter. In addition, mebendazole (three times daily 1000 mg) was administered for 13 months. The signs if inflammation receded and the cyst shrank to a small residual volume. Surgical intervention became unnecessary.