Sudden stomach pain is caused by stomach cramps, gastric ulcers, gastric perforation and other factors. Most episodes of stomach cramps are sudden, during which the smooth muscle of the patient’s stomach wall will contract and spasm strongly, resulting in painful sensations. Most of the pain caused by gastric spasm is self-limiting and will relieve itself after a period of episodes. For people with severe and long-lasting pain, antispasmodic and analgesic drugs can be used to relieve it. Patients with gastric ulcers will also experience sudden pain in the stomach when the gastric acid secretes too much, and the pain of gastric ulcers has a certain regularity, mainly occurring about an hour after meals. In the case of gastric perforation, not only will there be severe pain in the stomach, but the acid in the stomach will also enter the abdominal cavity through the perforation, and even induce abdominal infection as a result.