Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic procedure used to treat bile duct stones, obstructive jaundice, biliary leaks, and a variety of other conditions. There is active debate whether antibiotics should be given prophylactically for ERCP outside of high risk indications including primary sclerosing cholangitis. In part this is due to a lack of appropriately powered clinical trials with adequate follow up. The aim will be to assess whether prophylactic antibiotics decrease the rate of post ERCP cholangitis as defined by the Revised Tokyo Criterion.