Absolute or functional iron deficiency is the most prevalent cause of anaemia in surgical patients, and its correction is a fundamental strategy within "Patient Blood Management" programmes. Offering perioperative oral iron for treating iron deficiency anaemia is still recommended, but intravenous iron has been demonstrated to be superior in most cases. However, the long-standing prejudice against intravenous iron administration, which is thought to induce anaphylaxis, hypotension and shock, still persists. With currently available intravenous iron formulations, minor infusion reactions are not common. These self-limited reactions are due to labile iron and not hypersensitivity. Aggressively treating infusion reactions with H1-antihistamines or vasopressors should be avoided. Self-limited hypotension during intravenous iron infusion could be considered to be due to hypersensitivity or vascular reaction to labile iron. Acute hypersensitivity reactions to current intravenous iron formulation are believed to be caused by complement activation-related pseudo-allergy. However, though exceedingly rare (<1:250,000 administrations), they should not be ignored, and intravenous iron should be administered only at facilities where staff is trained to evaluate and manage these reactions. As preventive measures, prior to the infusion, staff should inform all patients about infusion reactions and identify those patients with increased risk of hypersensitivity or contraindications for intravenous iron. Infusion should be started at a low rate for a few minutes. In the event of a reaction, the very first intervention should be the immediate cessation of the infusion, followed by evaluation of severity and treatment. An algorithm to scale the intensity of treatment to the clinical picture and/or response to therapy is presented.