The order of responses of cell systems of organs and changes in the content of some proteins of mouse and dog blood in response to addition of natural (alpha-tocopherol) and synthetic (ionol) antioxidants was studied at the whole-body level using ERP spectroscopy, radioisotope analysis, and chemiluminescence technique. Responses were evaluated by the temporary and concentration-dependence changes in the activity of ribonucleotide reductase and the rate of protein and DNA synthesis in organs of mice, as well as by the changes in the pools of Fe3+ -transferrin and Cu2+ -ceruloplasmin in blood and the antiradical activity of blood plasma of dogs and mice. During the first 24 h of exposure to alpha-tocopherol, the activity ribonucleotide reductase in bone marrow rapidly increased, whereas the activity of this enzyme and the rate of DNA synthesis in the thymus and spleen were suppressed by 30-50% compared to the control. The changes in these parameters had a phase mode with maxima on days 2-3 and 6-8. The stimulatory effect of the antioxidant on the processes of synthesis was concentration-dependent. We found that the optimal stimulation of the synthesis of deoxyribonucleotides, DNA, and protein was achieved by single administration of alpha-tocopherol at a dose of 20 mg per dog with an average weight of 15 kg and 17 mg/kg in the case of mice. Single or repetitive administration of higher doses of alpha-tocopherol was either ineffective or even suppressed the synthesis of DNA and deoxyribonucleotides. Ionol administered at a dose of 60 mg/kg increased DNA and protein synthesis in mouse organs in 2-4 and 1.2-1.5 times, respectively, compared to the control. It was also shown that single and repetitive administration of alpha-tocopherol to dogs increased the pool of Fe3+ -transferrin and Cu2+ -ceruloplasmin in blood in 2-3 times and by 20-30%, respectively, compared to the control. It is suggested that changes in Fe3+ -transferrin pool in peripheral blood may be used for evaluation of the stimulatory effect of antioxidants on the synthesis of macromolecules in organs and for the determination of dependence of this effect on the concentration of antioxidants.