Gastrointestinal (GI) complications after surgery requiring cardiopulmonary bypass (CPB) can be serious, often lethal events. In our study, from 1970 through 1981 there were 43 such complications after 5080 CPB cases (0.85%). We noted on annual persistent occurrence of approximately 1%. The overall mortality rate was 63%. The most frequent complication was hemorrhage (usually gastroduodenal). Other complications encountered were pancreatitis, cholecystitis, hyperbilirubinemia, bowel perforations or infarcts, and gastroduodenal alterations. We concluded that GI complications after CPB are associated with a high mortality rate and often occur with other complications. Careful judgment is needed for appropriate diagnosis and therapy.