Endoscopic Retrograde Cholangiopancreatography (ERCP) combines the use of a flexible, lighted scope (endoscope) with X-ray pictures to examine the tubes that drain the liver, gallbladder, and pancreas. The endoscope is inserted through the mouth and gently moved down the throat into the esophagus, stomach, and duodenum until it reaches the point where the ducts from the pancreas (pancreatic ducts) and gallbladder (bile ducts) drain into the duodenum.