Gastroesophageal reflux mainly refers to symptoms such as heartburn and acid reflux caused by the reflux of gastroduodenal contents into the esophagus. It is caused by several factors: first, abnormalities in the structure and function of the anti-reflux barrier. If the patient has an esophageal hiatal hernia or achalasia after surgery, or if the intra-abdominal pressure is increased, such as when the patient is obese, has ascites, is pregnant or is working, the patient will have increased intra-gastric pressure at this time, which can cause structural damage to the lower esophageal sphincter. If foods such as high fat or chocolate are consumed, the cardia can be dysfunctional or the lower esophageal sphincter can be prolonged by transient relaxation. This can cause damage to the esophagus due to insufficient clearing capacity or barrier mucosa. Second, decreased esophageal clearance is commonly associated with diseases or pathophysiological processes that cause abnormal esophageal peristalsis or salivary secretion, such as dry syndrome. When a hiatal hernia occurs, part of the stomach or trans-septal esophageal hiatus enters the thoracic cavity changing the structure of the lower esophageal sphincter, which can also reduce esophageal clearance of reflux, causing GERD. There is also a decrease in the barrier function of the esophageal mucosa. If the patient has long-term smoking, drinking alcohol, or taking irritating food or medication, the esophageal mucosa will not be able to resist the damage of reflux, which leads to GERD.