I. Overview Iron deficiency anemia is a kind of anemia formed by the decrease of hemoglobin synthesis due to the lack of iron in human body’s storage, with small cell hypochromic anemia as the typical manifestation. Iron deficiency anemia is the final manifestation of iron deficiency in the body. Iron deficiency is the most common nutritional deficiency in the world, and iron deficiency anemia is the most common nutritional anemia, mostly seen in women and children of childbearing age. The clinical features are low red blood cell count and hemoglobin. II. Etiology and pathogenesis 1. Increased need and insufficient intake. Iron deficiency can occur in infants, adolescents, menstruating, pregnant and lactating women with increased iron requirements, and in severe cases, iron deficiency anemia. 2.Iron absorption disorder. After gastrointestinal surgery, especially after gastrectomy, the absorption of iron is affected due to the shortening of food passage time through the stomach and jejunum. 3.Excessive iron loss. Chronic blood loss is the primary cause of iron deficiency. It is seen in chronic gastrointestinal blood loss, gastrointestinal tumors, parasitic infections, excessive menstruation, recurrent nosebleeds, hemorrhoids, etc. The most common cause of iron deficiency anemia in adult men is chronic blood loss in the digestive tract, and the specific cause of blood loss should be identified if iron deficiency anemia occurs; the most common cause of iron deficiency anemia in adult women is excessive menstruation. The principles of treatment for iron deficiency anemia: etiological treatment and iron supplementation. 1. General treatment: Change the unreasonable diet structure and encourage more iron-rich foods with high absorption rate such as meat or iron-fortified foods. Infants and children should add supplemental food in time. Preventive iron supplementation can be considered during menstruation, especially for women during pregnancy. Identify the cause and treat the original disease. 2, drug treatment: (1) oral iron oral iron is convenient, safe, is the preferred method of treatment of the disease. -0,6, 3 times a day, 300mg per tablet (containing 60mg of elemental iron); ferrous sulfate controlled release tablets (Frontenac): 1 tablet, 1 time a day, 525mg per tablet (containing 105mg of elemental iron); ferrous fumarate: 1 – 2 tablets, 3 times a day, 200mg per tablet (containing (containing elemental iron 70mg); Ferrous gluconate: 0.3 – 0.6, 3 times a day, 300mg per tablet (containing elemental iron 34.5mg); Ferrous succinate (Sulforaphane): 200 – 400mg per day; Iron polysaccharide complex ( Ligustrum): 150mg twice a day, change to 150mg once a day after 4 weeks. Tea, milk, coffee and antacid drugs are not conducive to iron absorption and should be avoided at the same time. (2) Injectable iron: It can be used for those who have gastrointestinal diseases and cannot tolerate oral iron or aggravate the original disease after taking oral iron. Total dose of iron (mg) = [normal hemoglobin (g/dL) – patient hemoglobin (g/dL)] × 300 + 500 Commonly used iron dextran, containing 50mg of iron per ml, the first 25 – 50mg, intramuscular injection, if no allergic reaction the next day 50 – -100mg, intramuscular injection, once every 1–3 days, contraindicated in hepatic and renal insufficiency. IV. Prognosis assessment After the cause of iron deficiency is removed, the disease can be cured. However, some patients are chronically anemic because they cannot remove the primary cause or cannot adhere to iron supplements.