In this prospective multicenter randomized clinical trial the investigators assign patients referred for therapeutic biliary ERCP and difficult biliary cannulation (unsuccessful cannulation after 5 minutes) to early precut (group A) or repeated papillary cannulation attempts followed, in case of failure, by late precut (group B). Group A patients undergo precut immediately after randomization ("early precut"), while for group B cannulation attempts are continued for another 10 minutes, after which a precut is done if these fail or there are three unintended additional passages of the guide-wire into the MPD ("delayed precut").