An Endoscopic Retrograde Cholangiopancreatography is a procedure that uses an endoscope or a thin flexible probe fitted with a camera to examine the pancreas, the pancreatic duct, the common bile duct, the gall bladder, the hepatic duct, and duodenal papilla. It is similar to an upper endoscopy and the probe is passed through the mouth to the stomach and duodenum. Following this, a catheter is passed through this probe that proceeds into the pancreatic duct and other organs. Often a dye is injected through this catheter. This lights up the organs and allows the doctor to capture images or take x-rays. ERCP is of immense value in diagnosing diseases of the gall bladder, pancreas, bile, and pancreatic ducts. It is done to diagnose blockages of these ducts, in cases of pancreatitis, suspected cancers of the pancreas or gall bladder.