Bowel obstructions may be due to mechanical or functional causes. Although acute colonic pseudo-obstruction (ACPO) falls into the latter category, we must ALWAYS rule out mechanical causes for massive distension of the colon.  In this episode, we make our way down the GI tract and discuss the pathophysiology, risk factors, diagnostic and therapeutic considerations for what Dr. Ogilvie coined "Large-intestine Colic" in 1948.