Gastritis is usually not cancerous, while gastric ulcer has the risk of cancer. Gastritis is a chronic inflammation of the gastric mucosa, which can manifest clinically as stomach pain, bloating and indigestion, and does not carry the risk of cancer. Gastric ulcer, on the other hand, has the risk of cancer, because gastric ulcer is caused by the rupture of gastric mucosa and eventually forms ulcers due to various pathologies. Because the secretion of gastric acid can be stimulated after meals, gastric acid can stimulate the ulcer surface and lead to the aggravation of gastric ulcer symptoms, and a small number of gastric ulcer patients can progress to gastric cancer. Therefore, if a gastric ulcer is found clinically, a specimen should be kept for pathological examination to clarify whether it is a benign ulcer or a malignant ulcer. Benign ulcers usually have a better prognosis, while malignant ulcers should be treated by surgery as soon as possible.