Gastrointestinal complications such as peptic ulcer disease, pancreatitis, acute cholecystitis, bowel ischaemia, and diverticulitis are rare after cardiac surgery (< 1%), but are associated with high morbidity and mortality (about 30%). Hypoperfusion during cardiopulmonary bypass seems a possible aetiological factor. As many patients may be mechanically ventilated and sedated, the usual symptoms and signs of an abdominal complication may be masked. It is necessary to keep this possibility in mind in patients with abdominal pain or tenderness, and the usual diagnostic measures should be undertaken if time permits. Initial treatment is usually conservative, but when it fails, prompt intervention is obligatory. Unfortunately surgeons are often reluctant to submit patients to major abdominal operations immediately after cardiac surgery. However, effective and timely intervention may be life-saving in patients who are poorly able to compensate for the major haemodynamic disturbances of the untreated serious bleeding or sepsis. Although the cardiac condition must be taken into consideration, most patients' cardiac function will have improved since their open-heart surgery and they should be able to withstand general anaesthesia and most operations.