A 73-year-old man had a low anterior resection for a villous adenoma in the rectosigmoid. On the 4th day after surgery, he suddenly developed severe interscapular pain. Aortic dissection was ruled out, but endoscopy showed black mucosa of the entire esophagus. With conservative treatment, including proton pump inhibition, he recovered completely. We hypothesize that a transient gastric outlet obstruction and massive gastroesophageal reflux played a significant role in the etiology of this rare and alarming, but, in this case, completely reversible, syndrome.