Signal 1: Change in the nature of pain. Ulcer disease is characterized by regular pain. Gastric ulcers are full meal pains, which appear half an hour to two hours after a meal and disappear by the next meal. Duodenal ulcers are hunger pains, also called fasting pains, which appear 3 to 4 hours after meals and last until the next meal, and the pain can be reduced or disappear completely after eating. If the ulcer occurs in the pylorus of the stomach close to the duodenum, the pain rhythmicity is the same as that of duodenal ulcer. Once the nature of the pain of gastric ulcer has changed to persistent pain or reduced, you should be alert to the possibility of cancer and go to the hospital for early examination. Pain, perhaps, is something we are all used to, because we often have such and such pain in our lives. Therefore, when many people feel soreness or a certain joint pain, almost no one will buy medicine for this purpose as long as they can’t bear it… Signal 2: Obvious weight loss. Any patient with gastric ulcer above the age of 40 years old who has a short-term loss of appetite, anorexia of meat, nausea, vomiting, vomiting of the next food or dark red food, poor nutritional status, significant weight loss, fatigue and weakness, and the effect of drug therapy becomes worse, this may be a signal of malignant change. Signal 3: The appearance of a fixed mass. Some patients with gastric ulcer can feel a lump in their heart fossa, hard and not smooth surface, and the lump increases rapidly and is painful to press. With the increase of the mass, vomiting is also aggravated, this situation is mostly the occurrence of malignant changes. Signal 4: Unexplained black stool. Generally, black stools can be seen after eating a lot of blood from animals such as pigs, sheep and chickens, or after taking certain drugs. If an ulcer patient has unexplained black stool or persistent blood in the stool, special attention should be paid to further investigation, which is often a precursor symptom of malignancy. If any one of the above conditions is present, you should immediately go to the hospital and have the relevant aspects examined.