Reflux in the mouth may be caused by gastroesophageal reflux, but also gastritis (or gastrointestinal dysfunction) and pharyngeal disorders and other factors, as follows: Gastroesophageal reflux: It is a gastroesophageal dysfunction caused by abnormal structure and function of anti-reflux barrier (e.g., after surgery for pancreatic achalasia, increased intra-abdominal pressure, long-term increased intragastric pressure, etc.), decreased esophageal clearance, and decreased barrier function of esophageal mucosa, etc. It is a gastroesophageal dysfunction disorder that is mainly caused by the dysfunction of the lower esophageal sphincter. Typical symptoms of GERD include stomach pain and acid reflux, heartburn, etc. Gastritis (or gastritis) is the most common form of gastric reflux. 2. Gastritis (or gastrointestinal dysfunction): excessive secretion of gastric acid in the stomach, accompanied by a decline in gastric defenses, can lead to the upward movement of fluids in the stomach, resulting in acid reflux and water retention in the mouth. 3. Pharyngeal diseases: some pharyngeal diseases such as pharyngeal muscle paralysis, retropharyngeal abscess, laryngopharyngeal tumors, etc., can appear dietary reflux, which is manifested as the reflux of food and drink to the oral cavity, nasopharynx and nasal cavity instead of smoothly passing through the pharynx to enter the esophagus, which is also known as palatopharyngeal reflux, and it is often accompanied by difficulty in swallowing. If the symptoms continue to be unrelieved, it is recommended to consult a doctor in a timely manner to clarify the cause of the disease and target treatment under the guidance of the doctor, do not take medication on your own to avoid delaying the condition.