Frequent nighttime stomach pains are caused by gastric ulcers, duodenal ulcers, and pyloric obstruction. When nighttime stomach pain occurs about two hours after a meal, it is mostly caused by gastric ulcer disease. Patients with gastric ulcer secrete a lot of gastric acid after eating food due to the digestion of food, and once the gastric acid comes in contact with the ulcer surface, stomach pain will occur. When nighttime stomach pain is in the middle of the night, it is mainly caused by duodenal ulcer disease. Patients with duodenal ulcer have their stomach emptied of food in the middle of the night, and since there is no food in the stomach to neutralize it, stomach acid will enter the duodenum as it is, causing an invasion of the duodenal mucosa and thus causing a painful sensation. In some people, nocturnal stomach pain is a bloating pain, accompanied by nausea and vomiting, which is associated with pyloric obstruction. When pyloric obstruction occurs, food cannot be expelled, so it ferments and rots in the stomach, causing stomach pain, nausea, and vomiting.