Post-ERCP pancreatitis is likely due to the patient's inflammatory response to duct instrumentation during the procedure and severity is based on the magnitude of this response. Phospholipase A2 (PLA2) plays a pivotal role in inflammation since it regulates many pro-inflammatory mediators, including prostaglandins, leukotrienes, and platelet activating factor. NSAIDs inhibit PLA2, and indomethacin is the most potent clinically available PLA2 inhibitor. Our study hypothesis is that treatment with indomethacin will reduce the inflammatory response to ERCP, and therefore lessen the incidence and severity of post-ERCP pancreatitis.