1. The complex compound iron (III) -pyrazin-2-ol-1-oxide or its pharmaceutically acceptable salts for use in the treatment and prevention of the phenomena of iron deficiency and iron deficiency anemia, as well as their accompanying symptoms. A complex compound of iron (III) for use according to claim 1, containing at least one ligand of the formula (I): where the arrows indicate the coordination bond with one or different iron atoms, R, R, R can be the same or different and are selected from a group consisting of: hydrogen, halogen, optionally substituted alkyl, optionally substituted alkoxyl, optionally substituted aryl, optionally substituted alkoxycarbonyl and optionally substituted aminocarbonyl, or R, R together with the carbon atoms to which they are bonded if necessary, form a substituted 5- or 6-membered saturated or unsaturated ring, which may optionally contain one or more heteroatoms, or pharmaceutically acceptable salts thereof. 3. A complex compound of iron (III) for use according to claim 2, containing at least one ligand of the formula (I): where the arrows indicate the coordination bond with one or different iron atoms, R, R, R can be the same or different, and selected from the group consisting of: hydrogen, optionally substituted alkyl, halogen, or R, R, together with the carbon atoms to which they are attached, form a 5- or 6-membered carbocyclic ring, or pharmaceutically acceptable salts thereof. 4. A complex compound of iron (III) for use according to claim 3, containing at least one ligand of the formula (I): where the arrows indicate the coordination bond with one or different iron atoms, R, R, R can be the same or different and select1. Комплексное соединение железо (III)-пиразин-2-ол-1-оксидг или его фармацевтически приемлемые соли для применения при лечении и профилактике явлений дефицита железа и железодефицитной анемии, а также сопровождающих их симптомов.2. Комплексное соединение железа (III) для применения по п. 1, содержащее, по меньше
