For decades intravenous iron was considered dangerous. Newer formulations with carbohydrate cores binding elemental iron more tightly allow complete iron replacement within 15-60 min in one visit. Meta-analyses and prospective comparisons of different formulations support equivalent safety to placebo with less toxicity than oral iron. Of the available formulations, the preponderance of published evidence supports equal safety and efficacy. In this Viewpoint, we report evidence supporting repositioning of intravenous iron to the frontline in multiple disorders with iron deficiency, which include heart failure, chronic kidney disease, inflammatory bowel disease, patient blood management in the perioperative period, and obstetrics and gynaecology. We have also highlighted neonatal evidence supporting the inadequacy of oral iron in late pregnancy, a critical period of iron need for normal foetal brain development. Physicians should consider prioritising the use of intravenous iron rather than oral iron as a treatment for iron deficiency in some of these clinical scenarios.