Endoscopic retrograde cholangiopancreatography (ERCP) is a medical procedure used to diagnose and treat conditions affecting the bile ducts and pancreatic ducts. During ERCP, an endoscope is inserted through the mouth, down the esophagus, and into the stomach and duodenum. Then, a catheter is passed through the endoscope into the ducts, and contrast dye is injected to make the ducts visible on X-ray images. This allows the doctor to identify blockages, strictures, stones, or other abnormalities in the bile or pancreatic ducts. Additionally, therapeutic interventions can be performed during ERCP, such as removing gallstones, widening narrow ducts, or placing stents to relieve obstructions. ERCP is an important tool for diagnosing and treating conditions such as gallstones, bile duct strictures, pancreatitis, and pancreatic cancer.