Oral iron supplements are preferred for their safety and reliability. There are many types of iron supplements, but it is advisable to use ferrous iron preparations with higher potency, such as ferrous sulfate, ferrous fumarate and ferrous gluconate, etc. The daily dose should contain 150-200 mg of elemental iron. The daily dose should contain 150-200 mg of elemental iron and most patients tolerate oral iron well. A few patients may experience GI irritation, such as nausea, heartburn, gastrointestinal cramps and diarrhea, etc. They may start with a small dose and increase to the full dose after a few days. Iron can be taken at the same time as or after meals to reduce its side effects, but also to reduce its absorption. Drinking tea affects the absorption of iron, so it is not necessary to take it at the same time. Vitamin C helps iron absorption and can be used in combination. After taking iron, patients’ reticulocytes start to rise and reach a peak in 7-10 days, which can be used to judge the efficacy of treatment. Hemoglobin mostly starts to rise after 2 weeks of treatment and returns to normal after 1-2 months. After the hemoglobin is normal, iron should be continued for 3-6 months to replenish the body’s iron reserves and prevent relapse. The side effects of iron injection are more and more serious, and the indications should be strictly controlled 1, can not tolerate oral iron; 2, original gastrointestinal diseases, oral iron aggravates the disease, such as ulcerative colitis, gastroduodenal ulcer, etc.; 3, digestive tract absorption disorders, such as after gastroduodenectomy, atrophic gastritis, etc.; 4, due to treatment can not maintain iron balance, such as hemodialysis. The total dose should be calculated before iron injection treatment, and the formula is: total iron supplement dose (mg) = [normal hemoglobin – patient hemoglobin (g/L)] × body weight (kg) × 0.24 + 500mg.