ERCP is a procedure that enables your physician to examine the pancreatic and bile ducts. A bendable, lighted tube (endoscope) about the thickness of your index finger is placed through your mouth and into your stomach and first part of the small intestine (duodenum). In the duodenum a small opening is identified (ampulla) and a small plastic tube (cannula) is passed through the endoscope and into this opening. Dye (contrast material) is injected and X-rays are taken to study the ducts of the pancreas and liver.