Changes in the functional activity of the synthesis apparatus of rat blood lymphocytes under different scheme in application of bioadditive Soma after acute X-irradiation by fluorescent microspectrometry. Some metabolic indices in animals were investigated too. It has been shown the bioadditive Soma using in norm reliably increased the synthetic activity on days 13 and 20. Preliminary Soma using during a month followed by the same interval increased the animal radioresistance (scheme 1), while the Soma using immediately after irradiation (scheme 2) revealed no pronounced radioprotective effect. It was found the Soma increased metabolism that may be important to recover homeostasis. The results show the expediency of further investigation of the Soma radioprotective properties with different concentrations and schemes as well as the necessity of monitoring the immune system during Soma using.