Endoscopic retrograde cholangiopancreatography is an endoscopic technique used to investigate and treat diseases of the biliary tract, pancreatic duct, and gallbladder. The bile ducts are the tubes that carry bile from the liver and gallbladder; The pancreatic duct carries pancreatic juice from the pancreas. Both of these tubes empty into the duodenum, which is the first part of the small intestine. So how is endoscopic retrograde cholangiopancreatography performed?