The main causes of gastroesophageal reflux are: impaired anti-reflux structures and functions, reduced clearance of the esophagus, and decreased resistance of the esophageal mucosa. 1. Impaired anti-reflux structure and function: the lower esophageal sphincter is a structure that prevents reflux of gastric contents and acts as a high-pressure barrier. When the intra-abdominal pressure rises, after cardia surgery, or when there is a delay in gastric emptying, the structure and function of the lower esophageal sphincter can be damaged, which can lead to the reflux of gastric contents into the esophagus and the emergence of gastroesophageal reflux. 2. Reduced clearance of the esophagus: The normal esophagus can perform its own peristalsis and neutralize saliva to clear reflux. When diseases such as dry syndrome are present, the peristaltic rate of the esophagus slows down, leading to a decrease in the clearing effect of the esophagus, which in turn prevents the removal of some of the residual reflux, resulting in gastroesophageal reflux. 3. Decreased resistance of esophageal mucosa: For example, long-term heavy smoking, alcoholism, eating too much spicy and stimulating food, resulting in decreased resistance of esophageal mucosa, which in turn affects the anti-reflux defense mechanism of the esophagus, increasing the probability of gastroesophageal reflux. Thus, the occurrence of GERD is closely related to the function of the esophagus and the lower esophageal sphincter. In addition, some depression, anxiety and other psychosomatic factors can also induce GERD.