Examination of major duodenal papilla (MDP) using a side-viewing duodenoscope is a golden standard. However, side-viewing duodenoscope is not available in some endoscopic centers. Cap-assisted esophagogastroduodenoscopy (Ca-EGD) using a transparent cap fitted to the tip of the scope has emerged as an alternative method for the observation of MDP. A recent study showed that complete examination of MDP could be achieved in 97% of patients. The investigators hypothesize that Ca-EGD is non-inferior to duodenoscope for the observation of MDP.