For iron deficiency anemia with a clear diagnosis, the safer and more effective oral iron supplements are preferred. Iron supplements of divalent iron, such as ferrous sulfate, ferrous fumarate, ferrous succinate, and iron amino acid chelate, are more commonly used clinically, and are safer and more effective. The choice of iron is usually based on the iron content, absorption rate and cost effectiveness, as well as the patient’s tolerance level. Most oral iron supplements have mild gastrointestinal reactions. If patients have severe gastrointestinal reactions after taking them, such as stomach discomfort, nausea, vomiting, etc., they can switch to oral iron supplements with less gastrointestinal reactions, such as ferrous succinate oral solution, but they are relatively more expensive. For patients with severe gastrointestinal reactions and GI disorders, such as peptic ulcers, oral iron may not be available. Treatment with intravenous iron supplementation is usually available and iron sucrose is commonly used clinically. Iron supplementation requires strict indications and accurate calculation of the patient’s iron needs before careful application.