The majority of gastric cancer patients can be accompanied by different degrees of anemia, the main reasons are as follows: 1. Long-term chronic bleeding from tumor surface and progressive aggravation of bleeding, long-term chronic blood loss in the digestive tract may cause anemia; 2. Stomach has absorption function, especially hemoglobin production requires large amount of iron. Gastric acid is an important way to help iron absorption. If it is gastric cancer, it will produce low gastric acid and gastric hypogastric function, and the digestive and absorption function will also be reduced, which may lead to malnutrition anemia. Gastric cancer anemia is mostly caused by malnutrition and long-term chronic massive blood loss caused by gastric cancer, so most of gastric cancer patients can be accompanied by different degrees of anemia.