Gastric cancer is a malignant tumor originating from the epithelium of the gastric mucosa, accounting for 95% of gastric malignancies and is one of the common diseases threatening human health. The age of onset of gastric cancer is mostly seen between 40-60 years old, and it is more common in men than women. Early gastric cancer mostly has no obvious symptoms. Some patients may have non-specific upper gastrointestinal symptoms, including upper abdominal fullness and discomfort or hidden pain, acidity, belching, nausea, loss of appetite, vomiting and occasionally vomiting blood and black stool, etc. Among them, upper abdominal discomfort is the most common, which can often be relieved after symptomatic treatment. Because these symptoms are often not taken seriously by patients, they are often mistaken as gastritis or ulcer disease and lead to delay in diagnosis and treatment. In addition to the above mentioned symptoms, progressive gastric cancer may also have complications such as obstruction, bleeding and perforation. When the tumor involves the cardia, it can cause progressive dysphagia; when the sinus cancer involves the pylorus, it can cause pyloric obstruction, which is manifested as epigastric fullness and vomiting of food after eating. In case of upper gastrointestinal bleeding, only occult blood in stool is positive when the bleeding volume is small, while vomiting blood or black stool when the bleeding volume is large. Stomach cancer perforation may present with severe abdominal pain. Most patients are accompanied by systemic symptoms such as loss of appetite, emaciation, weakness, etc. Advanced stage is often accompanied by fever, anemia, edema of lower limbs and cachexia (generalized muscle atrophy due to long-term malnutrition). As mentioned above, the symptoms of gastric cancer are often atypical, so it is easy to dismiss them as gastritis. For patients over 40 years old, if the above symptoms appear, they should seek medical treatment in time to avoid delaying the disease and treatment.