Barrett's esophagus or intestinal metaplasia (IM) is a change in the epithelial lining of the esophagus. Barrett's esophagus develops as a result of chronic exposure of the esophagus to refluxed stomach acid and enzymes, as well as bile, resulting in recurrent mucosal injury. Injury is accompanied by inflammation and, ultimately, a cellular change (metaplasia) to a specialized columnar epithelium (Spechler SJ. Barrett's Esophagus. N Engl J Med 2002;346(11):836-842.)