The importance of risk factors in the development of radiation-related enteric damage has been demonstrated. Ninety-two women with ovarian tumors received 2000 rads to the abdomen, followed by an additional 2975 rads to the pelvis. By analyzing the development of small bowel obstruction in these women and in other series from the literature, it appears that more than half of enteric complications can be attributed to factors such as prior surgery, thin physique, and preexisting vascular damage. These constitutional factors often will have a greater effect on the development of small bowel damage than will radiation dose, volume, or time. By taking such factors into account and by substituting alternative forms of therapy when feasible, morbidity secondary to radiotherapy can be substantially reduced.