Radiation enteritis is a functional disorder of the intestine that occurs during or after a course of radiotherapy to the abdomen, pelvis or rectum. It presents in both an acute and chronic form and has sequelae that can be life threatening. As radiotherapy is now being used more than ever before in the treatment of solid organ malignancies in the abdomen and pelvis, the incidence of radiation enteropathy is likely to increase in the future. We present two patients with severe forms of this condition in order to clarify the salient issues regarding its diagnosis and, in particular, its distinction from mechanical bowel obstruction. We also review its pathophysiology, management and current preventative strategies.