Frequent stomach pain and acidity are associated with reflux esophagitis, gastritis, gastric ulcer, and duodenal ulcer. The occurrence of stomach pain and stomach acid is mostly caused by excessive secretion of stomach acid causing irritation to the mucous membrane of the digestive system, especially when spicy, greasy and irritating foods are eaten. When excessive secretion of gastric acid is accompanied by relaxation of the cardia sphincter, gastric acid will more easily reflux into the esophagus and induce the onset of reflux esophagitis. The pain in patients with reflux esophagitis is mainly pain in the sternal area, accompanied by acid reflux, belching and difficulty in swallowing. Gastritis is caused by congestion and edema of the gastric mucosa. Patients with gastritis will experience pain when eating food that rubs against the mucosa of the stomach wall. The pain caused by gastritis is not regular and can occur from time to time, but is milder in nature. When ulcerated surfaces appear on the gastric mucosa, the stomach acid is more likely to corrode the stomach wall and cause pain, and the pain caused by gastric ulcers is regular, mainly occurring about an hour after a meal. Duodenal ulcers also frequently cause stomach pain and acid reflux in the stomach. The nature of the pain in patients is hunger pain and midnight pain, and the pain is more intense and can even cause nausea and vomiting.