The present invention provides a composition comprising a chelated iron complex (55) for use in a method of treating iron deficient anaemia in a subject wherein the composition comprising the chelated iron complex is delivered to the subject by iontophoretic transdermal delivery of the composition, the method comprising: applying a patch (10) to the skin of a patient, the patch comprising an electrode (24, 26, 31, 36, 100) and a chelated iron complex (55), the chelated iron complex comprising an iron ion electrostatically bound to a chelating agent and wherein the chelated iron complex (55) comprises a therapeutically effective amount of iron for the treatment of iron deficiency, delivering an electrical current to the skin (20, 30, 24, 31, 21) using the electrode (24, 26, 31, 36, 100)； and utilizing the current to transport the chelated complex (55) across the skin (20, 30, 24, 31, 21), wherein the iron is substantially chromogenically unreactive with the skin during transport.
