Gastroesophageal reflux disease (GERD) occurs when the lower esophageal sphincter (LES) fails to prevent gastric contents from refluxing into the esophagus, causing tissue damage, inflammation, and characteristic symptoms. GERD affects approximately 20% of the adult population in Western countries and is one of the most common gastrointestinal conditions nurses will encounter. The LES is a ring of smooth muscle at the gastroesophageal junction that normally maintains a resting pressure of 10-30 mmHg, creating a barrier that prevents acidic gastric contents (pH 1-2) from entering the esophagus (which lacks the protective mucus lining that protects the stomach). In GERD, the LES tone is inappropriately low, allowing transient relaxations that permit reflux. Contributing factors include increased intra-abdominal pressure (obesity, pregnancy, ascites), delayed gastric emptying, hiatal hernia (displacement of the gastroesophageal junction above the diaphragm), and certain substances that relax the LES (caffeine, chocolate, alcohol, nicotine, fatty foods, peppermint). When acidic gastric contents contact the esophageal mucosa, they cause chemical injury to the squamous epithelium. Repeated acid exposure leads to inflammation (esophagitis), erosion, and potentially ulceration. Chronic GERD can cause Barrett esophagus, a...