astrointestinal disease is one of the serious complications that can follow after cardiac surgery, and can lead to high rates of morbidity and mortality. 1,2 Particularly, postoperative bleeding from the upper gastrointestinal (GI) system is quite lethal, because coagulopathy can develop as patients undergo anti-coagulant therapy. Therefore, prophylactic treatment for upper GI diseases after open heart surgery appears very necessary. Several investigators have reported the incidence and risk factors for stress ulceration and upper GI bleeding in patients after cardiac surgery. 3,4 However, there are no randomized controlled trials of the incidence of these lesions and the effects of prophylactic treatment in adult patients undergoing open heart surgery. We designed a prospective randomized trial to test the efficacy of different antisecretory agents, such as histamine-2 (H2)-receptor antagonists and a proton pump inhibitor (PPI) to prevent upper GI complications after open heart surgery.