Hirschsprung's disease is characterized by lower intestinal obstruction. In this retrospective study, we investigated the postoperative complications and the causes of death in pediatric patients with Hirschsprung's disease. Between January 1981 and June 1998, 147 patients with Hirschsprung's disease underwent surgical intervention (129 with both colostomy and Soave's pull-through procedures) at Mackay Hospital. Of 147 total patients, 83.67% had aganglionosis in the rectosigmoid, 5.44% had colon involvement, and 4.08% had total colon aganglionosis, documented pathologically after a Soave's pull-through procedure. Any post-pull-through patient who showed symptoms of fever, leukocytosis, diarrhea, and clinical sepsis was diagnosed with Hirschsprung's enterocolitis. Four patients died within 4.5 months of surgery, and one patient died more than 4 years after surgery; these five patients were positive for Thomsen (T-) antigen. One patient died soon after rectal irrigation was performed in preparation for the surgery. All five of these patients had sepsis clinically, and anaerobic sepsis was attributed as the main cause of their deaths. Of interest in these cases is the presence of T-antigen, a potentially useful marker for anaerobic bacterial infection that may not be well known to most pediatricians. We recommend (1) determining the presence of T-antigen in patients with recurrent Hirschsprung's enterocolitis, (2) administering empirical antibiotics with anti-anaerobic activity as soon as possible, and (3) irrigating the colon in those patients who develop sepsis after a pull-through procedure.