Patients with history of gastric disease should be alert to gastric cancer when there is a change in the regularity of symptoms of previous gastric disease after meal; patients without history of gastric disease should be alert to gastric cancer when there are symptoms of digestive system after meal. 1. Patients with history of gastric disease, such as patients with gastric ulcer for many years, should be alerted to the occurrence of gastric cancer if there is obvious change in the rhythm and symptoms of pain after meal. For patients with history of other gastric diseases, such as atrophic gastritis, gastric polyp, post-gastric resection, etc., if there is epigastric pain after meal, and the pain is not rhythmic and accompanied by fatigue and emaciation, they should be alert to gastric cancer. 2. For patients with no history of gastric disease, if they have epigastric discomfort at early stage, abdominal distension and nausea after eating, epigastric pain after disease development, loss of appetite, fatigue, emaciation, and obvious weight loss, they should be alert to the occurrence of gastric cancer. Especially patients over 40 years old with family history of stomach cancer should pay more attention to it. If there is any discomfort, it is recommended to actively seek medical treatment.