Iron supplements are takrn orally  to treat and prevent anemia due to iron deficiency (lack of enough iron that affects development of red blood cells causing reduction in number of red blood cells in the body).Iron is also used in the form of iron  dextran injection is used to treat iron deficiencies and iron deficiency anemia (low red blood cells) in severe deficiencies or when the patient cannot tolerate iron orally.Iron sucrose injection is used to treat iron deficiency anemia in people with kidney disease. It is usually given with another medication to promote the growth of red blood cells.