Columnar-lined esophagus or Barrett's esophagus is closely associated with gastroesophageal reflux disease. Animal and human studies have shown not only acid but duodenogastroesophageal reflux acting in synergy with acid causes the most esophageal injury. Patients with Barrett's esophagus manifest typical and atypical symptoms of reflux. Ten percent to 25%, however, have clinically silent reflux. Early diagnosis is essential for this disease as it is a risk factor for the development of adenocarcinoma of the esophagus.