After obtaining informed consent, subjects will undergo ERCP per clinical protocol. All procedure-related clinical decisions and interventions will be dictated by the performing physician as he or she sees fit. At the end of the procedure, it will be determined by the endoscopist and research coordinator whether the patient meets inclusion criteria. If inclusion criteria are met, subjects will be randomized by concealed allocation to receive either 100mg or 150mg indomethacin, in the form of two or three 50mg rectal suppositories. Those patients who are randomized to receive the 100mg dose will receive an additional glycerin suppository. Four hours later, those patients who were randomized to the high-dose group will then receive an additional 50mg suppository while in the recovery area. At this same time point, subjects who were randomized to the standard-dose group, will receive a glycerin suppository in the recovery area. All participating patients will receive a total of 4 suppositories.