Iron is one of the most important essential metal ions of which significance is well known for ages. This element is a key moiety of several enzymes in iron containing heme or nonheme form and transfer and storage protein, hemoglobin and myoglobin. Several membrane carriers of iron have already been identified. The redox state of iron is determined by xanthine oxidase, cytochromes and Hp or ceruloplasmin and ferroxidase activity of apo-ferritin, respectively. Some vitamins (C, B2-, B3-, B6-, B12) play also a role in the metabolism of iron. The iron content of cells of the organs is well regulated by the iron homeostasis. Iron has a significant role in the immune system by producing oxygen containing free radicals. Anaemia induced by iron deficiency may cause a challenge concerns for pregnant women, babies and adolescent, primarily.