Macrocytic anemia is an anemia in which the average volume of red blood cells in the peripheral blood exceeds 100 fL or more. Macrocytic anemia can be seen in a variety of diseases, one of the most common being megaloblastic anemia. Due to folic acid and vitamin B12 deficiencies, DNA synthesis is impaired, which prevents normal replication and division, resulting in an enlarged nucleus, which in turn causes an increase in the size of the red blood cells. Macrocytic anemia can be treated by supplementing with folic acid and vitamin B12, which has a good effect. In addition, macrocytic anemia can also be seen in hemolytic anemia patients, for hemolytic anemia patients, the first choice of treatment is to take glucocorticoid therapy, you can take prednisone acetate, dexamethasone and so on. If hormone therapy is ineffective, or hormone therapy is not tolerated, the spleen can also be removed. In addition, some patients with hyperplastic syndromes also develop macrocytic anemia. For myelodysplastic syndromes, the preferred treatment is the application of demethylation drug therapy, and the commonly used drug is decitabine.