Barrett's esophagus is a condition in which the lower portion of the esophagus changes, due to the chronic effects of stomach acid splashing back into the esophagus. The esophagus is the muscular tube that carries food and saliva from the mouth to the stomach. Barrett's esophagus is most common in those who suffer from gastroesophageal reflux disease, or GERD.

In Barrett's esophagus, the lining is replaced by a type of tissue that is similar to that normally found in the intestine. This process is called intestinal metaplasia.

Barrett's will often cause no symptoms at all, but a small number (less than 1%) of people with Barrett's can develop esophageal cancer.

Barrett's esophagus is diagnosed by upper gastrointestinal endoscopy and biopsy.