An investigation of iron metabolism in a female patient volunteer by administration of stable iron isotopes as tracers was performed. The applied methodology had already been tested in rabbits in comparison with radioactive tracer technique. The subject under study was given58Fe solution intravenously and about 45 min later57Fe solution orally. Ten blood samples were drawn at different times within 522 min from injection. Single iron isotopes content in plasma samples was determined by proton nuclear activation. A Compton suppressor system was utilized to improve the detector limits. The characteristic parameters of iron plasma clearance and of iron intestinal absorption were determined.