Malignant peptic ulcer should be noted if the patient has the following conditions: 1. The patient has a long past history of chronic gastric ulcer and is over 45 years of age. 2. The patient has no complications of peptic ulcer such as gastrointestinal bleeding, perforation or pyloric obstruction, but the rhythm of pain is lost and the oral treatment is less effective. 3. Barium meal examination of the upper gastrointestinal tract suggests the presence of gastric cancer. 4. The patient shows loss of appetite and weight loss, and the fecal occult blood test is persistently positive after repeated checks.5. After a course of strict medical treatment, about 6-8 weeks, the patient’s symptoms do not show any improvement. The presence of the above conditions should be considered whether the peptic ulcer is malignant.