Anemia symptoms are relatively common, and anemia is usually clinically classified into mild, moderate, and severe, and divided into acute or chronic anemia according to the degree of urgency of the patient’s onset. For the cause of acute anemia, it is mostly a sudden drop in hemoglobin, and it is usually considered that severe anemia mainly includes the following causes: 1. Bleeding: common gastrointestinal and urinary bleeding, patients will mostly experience a large and rapid drop in hemoglobin, and patients will experience hemorrhagic shock for a short period of time, which is life-threatening; if blood transfusion is not given in time, and then the causative factors and causes are removed, patients will have life-threatening conditions; 2. Acute hemolysis: the most The most common reason is the input of blood type incompatible blood, a large amount of blood type incompatible blood within a short period of time, such as the input of blood type A patients will appear acute hemolysis, which will lead to a short decline in hemoglobin, the patient will have a serious high fever, acute renal failure, if not treated urgently will be life-threatening; 3, rare acute hematopoietic dysfunction: this case is not only the problem of anemia, but also the problem of leukocytes and platelets. At the same time, white blood cells and platelets should drop, which is also very rare; its mainly seen in serious public events, like the atomic bomb incident in Japan, poisoning and other situations arise, and often acute anemia will also occur.