A study was conducted in rats and rabbits to histologically evaluate the effect of acute and late interruption of blood supply on the myenteric plexus located between the circular and longitudinal layers of the muscularis externa (Auerbach's plexus). An intestinal segment measuring 2 cm in rats and approximately 8cm in rabbits was sectioned and isolated on a mesenteric vascular pedicle. Animals in Group underwent clamping of the vascular pedicle for 1, 2, 3, 4, 5 or 6 h. There were 5 animals in each of these subgroups. Group : Intestinal segments with intact vascular pedicles were transferred from the abdominal cavity into the subcutaneous space. Groups with 5 animals in each underwent pedicle ligation immediately and at 1, 2, 3 or 4 weeks after the first operation. Three days later, histological studies were carried out. Injury to the myenteric plexus and the longitudinal muscle was observed in the viable intestinal segments when the mesenteric vascular pedicle was clamped for 4 to 5 h. Similar findings were observed when the pedicle was ligated within 1 to 2 weeks after grafting. The present results show that ischemia can cause injury to the myenteric plexus in the surviving intestine.