This document provides information about gastroesophageal reflux disease (GERD), including its definition, causes, symptoms, diagnosis, treatment, and prevention. GERD occurs when stomach acid returns up into the esophagus and can irritate its lining. Risk factors include hiatal hernia, obesity, smoking, and certain medications. Common symptoms are heartburn and acid regurgitation. Diagnosis is usually based on symptoms, but testing like pH monitoring of the esophagus may be used. Treatment involves lifestyle changes and medications to reduce acid production like PPIs. Surgery can help for severe cases, while weight loss can help prevent GERD.