Gastrointestinal complications after heart and heart-lung transplantation are being recognized and reported more frequently in the literature as a cause of significant morbidity. Between July 1983 and December 1989, 131 consecutive patients underwent 133 heart or heart-lung transplant procedures at The Johns Hopkins Hospital. Immunosuppression consisted of either cyclosporine and prednisone or cyclosporine, prednisone, and azathioprine. Twenty-eight patients (21%) had 38 gastrointestinal complications, including visceral perforations (n = 6), gastrocutaneous fistula (n = 1), retroperitoneal abscess (n = 1), cholecystitis (n = 5), gastric atony (n = 1), perianal abscess (n = 1), gastrointestinal bleeding (n = 4), esophagitis (n = 2), pancreatitis (n = 2), pancreatic abscess (n = 2), hepatitis (n = 2), cytomegalovirus infection (n = 3), and diarrhea (n = 8). Among this group of 28 patients, 17 operative procedures were needed by 13 patients (46%), for an incidence of major abdominal procedures in the entire transplant cohort of 10% (13/131). Operations included cholecystectomy (n = 5), colon resection with colostomy (n = 3), closure of perforated gastroduodenal ulcer (n = 3) and repair of gastrocutaneous fistula (n = 1), drainage of pancreatic abscess (n = 2), pyloroplasty (n = 1) and incision and drainage of perianal abscess (n = 1). The operative mortality rate was 8% (1/13). Overall survival in patients with gastrointestinal complications was no different than that in the entire transplant population. Age, gender, race, and number of rejection episodes did not correlate with the presence of gastrointestinal complications. Patients with gastrointestinal pathologic conditions necessitating surgery often had atypical presentations, with subtle clinical findings but with common general surgical problems.(ABSTRACT TRUNCATED AT 250 WORDS)