The invention provides methods and devices to reduce stomach acid secretion in a patient with a hyper acid condition. For example, the invention may involve ablation of the stomach lining to destroy acid-producing cells. Destroying acid-producing cells may reduce the amount of stomach acid produced and, therefore the amount of acid refluxed in the esophagus. The invention may further provide methods and devices to monitor the esophageal acid level before and after the ablation procedure.