The authors previously have demonstrated axonal necrosis of autonomic nerves in the surgically resected ilea of patients with Crohn's disease both in grossly normal ileal resection margins and in diseased areas. The present study of ileal stomal biopsies was carried out to obviate the possibility that the observed axonal damage might be related to the prolonged surgical manipulations required for ileal resection. The authors present studies of biopsies of ileal stomas and of small bowel from patients with Crohn's disease and various control disorders, including ulcerative colitis. Stomal biopsies were fixed immediately after they were obtained. Widespread, severe axonal necrosis of autonomic nerves was present in all Crohn's disease specimens, regardless of the patient's clinical status or the gross or routine microscopic evaluation of the same specimen. Controls either had no necrosis or displayed a minor degree of focal necrosis involving single axons. The authors conclude that Crohn's disease is accompanied by a severe and extensive necrosis of gut axons, and that such electron microscopic findings may serve to differentiate Crohn's disease from other inflammatory disorders.