Intravenous iron infusions rarely result in severe hypersensitivity reactions. The primary suspected hypersensitivity mechanism is an abnormal complement activation by non-IgE antibodies to the carbohydrate moieties stabilizing iron formulations. A major risk factor for hypersensitivity reactions is related to the infusion speed. Fishbane-like reactions usually resolve after pausing the infusion, which can be resumed under medical surveillance and at a lower infusion rate. Yet, anaphylactic reactions require emergency first aid and subsequent strict avoidance of intravenous iron. Desensitization protocols can be implemented in selected cases and under strict medical surveillance to reduce the risks of severe reactions upon re-exposure.