Gastric cancer patients usually do not have too many clinical signs, but some of them may have the following symptoms: 1) loss of appetite, fatigue, malnutrition, emaciation, and some patients may have acid reflux, belching, epigastric pain, etc.; 2) when gastric cancer reaches the advanced stage, pyloric obstruction, i.e., nausea and vomiting after eating, and some patients’ tumors, after eroding the blood vessels, can cause upper gastrointestinal hemorrhage, which will lead to vomiting of blood; 3) cancerous tumors may be perforated, which is called carcinomatous perforation, which will lead to severe pain in the whole abdomen, fever, and toxic shock.