The normal number of red blood cells is (4-10) × 10^9/L, most often combined with a decrease in hemoglobin, and this is called anemia. The main causes of anemia include malnutrition anemia and pernicious cell anemia. For iron deficiency anemia, you can take 3 tablets of ferrous sulfate orally, 3 times/day, plus vitamin C, 1 tablet, 3 times/day, to correct the anemia. For malnutritional anemia, folic acid plus vitamin B12 is given for treatment. For patients with anemia caused by leukemia and myelodysplastic syndrome, red blood cell transfusion can be given to improve the anemia, and chemotherapy can be applied to improve the treatment of the primary disease. After the primary disease is corrected, the red blood cells and hemoglobin will naturally increase.