[en] The radioprotective properties of selenium-comprising chicory phytocomposites (SECP) have been studied in a series of animal experiments. The prospectively of selenium as a basic material for food supplements and functional nutrition products for protection against acute and prolonged irradiation is demonstrated. The study demonstrates the radioprotective effect of the SECPE at both acute and prolonged irradiation exposure. This effect is based on the high biological activity of the SECPE which stimulates, regulates, and restores the psychoneuroimmune system and the non-specific resistance mechanisms. In our opinion, the SECPE radioprotective effect is most expressed at acute irradiation exposure. Based on the SECPE, we have elaborated a dietary food supplement with biological activity “Selenium-S”, which is promising both being used per se and for functional product development with the purpose of psychoneuroimmune regulation improvement including cases of radiation damage and requires further investigation of use peculiarities.