Food going back up into the mouth after a meal is associated with reflux esophagitis, pyloric obstruction, gastritis, gastric ulcer and other diseases. Reflux esophagitis is caused by the relaxation of the cardia sphincter, excessive secretion of gastric acid and other factors. During the attack of the disease, the stomach wall is stimulated by gastric acid and causes contraction and spasm, the contents of the stomach will be squeezed into the esophagus under pressure, and many people will even have the phenomenon of food going up into the mouth. In patients with pyloric obstruction, food cannot be emptied into the duodenum, so it remains in the stomach for a long time, and after abnormal fermentation, the pressure in the stomach increases, so food reflux occurs. In patients with gastritis and gastric ulcer, the digestive function of the stomach is affected during an attack, and food reflux can occur when the stomach wall is stimulated to contract and spasm.