Acute intestinal obstruction secondary to an idiopathic mesenteric hernia has been reviewed by collecting 139 reports from the literature and studying them from the standpoint of incidence, etiology, pathogenesis, clinical manifestations, diagnosis, treatment and mortality. An acute intestinal obstruction with strangulation in the absence of an external hernia and with no history of previous surgical procedures must suggest the possibility of an internal hernia, especially if the patient has a history of chronic intermittent abdominal distress and a palpable abdominal mass if found on examination.