Gastroesophageal reflux disease (GERD) is a condition in which the digestive acid in the stomach comes in contact with the esophagus. The irritation caused by this disorder is known as heartburn. Long-term contact between gastric acids and the esophagus can cause permanent damage to the esophagus and is associated with Barrett's esophagus. Esomeprazole reduces the production of digestive acids, thus reducing their effect on the esophagus.