Barrett's esophagus is a condition where the tissue lining the esophagus changes due to prolonged exposure to stomach acid, often from gastroesophageal reflux disease (GERD). This change is known as intestinal metaplasia, where the normal squamous cells are replaced by columnar cells, which are more resistant to acid. People with Barrett's esophagus have an increased risk of developing esophageal adenocarcinoma, a type of cancer. Regular monitoring through endoscopy is recommended for those diagnosed, as early detection can help manage potential complications. Treatment options may include lifestyle changes, medications, or surgery, depending on the severity of the condition.