Topicality. The widespread prevalence of tobacco smoking is a global problem of humanity, the solution of which is directed at the efforts of many scientists and professionals. At the same time, the distinctive feature of modern food technologies is the use of nutritional supplements. One of the most common nutritional supplements in Ukraine and in Europe is glutamate sodium (E621), which is not always safe for human health.Aim. To investigate degree of oxidative modification of proteins in serum of blood in rats during “passive tobacco smoking” on the basis of prolonged administration of monosodium glutamate in the sex and age aspects.Materials and methods. The study was conducted on 96 white, non-linear, sexually mature and sexually immature rats of both sexes. Each group of animals was divided into four subgroups: I – control; ІІ – rats, which were modeled «passive tobacco smoking»; ІІІ – rats, which were given glutamate of sodium; IV – rats, which were modeled «passive tobacco smoking» against the background of the introduction of glutamate sodium. Results and discussion. In the sexual aspect, the intensity of changes in the oxidation modification of proteins in serum exceeds those of the sexually active males under the condition of «passive tobacco smoking» – by 25.3 % for OMP370 and 31.5 % for OMP430; under the condition of “passive tobacco smoking” against the background of sodium glutamate – by 55,0 and 60,0 % respectively. When comparing the indicators of oxidative modification of proteins in blood serum of the sexually mature and immature males of control groups, lower values were recorded in immature animals.Conclusions. Based on the data obtained in the article, it can be argued that, excessive formation of free radical oxidation products under conditions of exposure to tobacco smoke and monosodium glutamate results in a marked increase in the oxidation modification of proteins. In the sexual aspect, the indicators of oxidative modification of proteins in the presence of passive tobacco smoking against the application of monosodium glutamate is increased more pronounced in females, and with the age-old comparison of changes in the degree of oxidative modification of proteins established its more intense increase in immature rats.