This document discusses various causes and radiological findings of large bowel obstruction. The most common causes are cancer (60%), diverticulitis (20%), and volvulus (5%). Radiological findings of large bowel obstruction include a peripherally located distended bowel with haustral markings and no air distal to the site of obstruction. Barium enema can demonstrate the level and degree of obstruction, and may show findings like an "inverted U-shaped" sigmoid loop or "bird's beak" sign in sigmoid volvulus. CT scan with oral and IV contrast is also useful to evaluate bowel obstruction and its underlying cause.