Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic procedure used to identify the presence of stones, tumors, or narrowing in the biliary and pancreatic ducts. After the endoscope is properly placed, a catheter is advanced in order to inject a contrast agent through the ducts. The contrast is visible on x-rays and allows a physician to evaluate the caliber, length, and course of the ducts. An ERCP may be performed if a patient experiences symptoms such as jaundice, abdominal pain, fever, or malabsorption.