During the past 10 years, the knowledge of iron metabolism has been revolutionized by the discovery of the main regulatory hormone of body iron: hepcidin. Meanwhile, new formulations of intravenous iron have been developed and are already or readily available. In this article, we review the recent pathophysiological mechanisms underlying anemia of chronic disease or due to iron deficiency. We describe the various treatment modalities of iron deficiency anemia using oral or intravenous route and the emerging indications of treatment with iron. Finally, we discuss the situations in which iron supplementation may be harmful