Sclerosing cholangitis may be due to developmental immunological, infective, vascular or chemical factors (1). Hydatid cysts of the liver may communicate with the biliary tree. This is the reason why intracystic injection of scolicidal solution before surgery may cause spreading of the solution into the bile ducts. This complication has already been described in literature (2,3). We present a new well-documented case of sclerosing cholangitis after the injection of formaldehyde into a hydatid cyst of the liver to kill it, and give some suggestions how to avoid this complication.