This document discusses several gastrointestinal diseases including gastroesophageal reflux disease (GERD), gastritis, and peptic ulcer disease. It defines each condition, describes symptoms, risk factors, diagnostic tests, and treatment options. GERD is caused by acid reflux and can cause esophagitis or complications like Barrett's esophagus. Gastritis is inflammation of the stomach lining that is often caused by H. pylori or NSAIDs. Peptic ulcers develop from an imbalance between acid and mucosal protection in the esophagus, stomach, or duodenum and may be associated with H. pylori. Treatment involves eliminating triggers, reducing acid production, and treating any underlying infections.