Endoscopic retrograde cholangiopancreatography, or ERCP, is a specialized technique used to study the ducts of the gallbladder, pancreas, and liver. Ducts are drainage routes; the drainage channels from the liver are called bile or biliary ducts.

During ERCP, your doctor will pass an endoscope through your mouth, esophagus and stomach into the duodenum (first part of the small intestine). An endoscope is a thin, flexible tube that lets your doctor see inside your bowels. After your doctor sees the common opening to ducts from liver and pancreas, your doctor will pass a narrow plastic tube called a catheter through the endoscope and into the ducts. Your doctor will inject a contrast material (dye) into the pancreatic or bilary ducts and will take x-rays.