It is known that flurenizide is a newly synthesized drug with pronounced antimicrobial, immunomodulatory functions. However, its effect on the functional properties of cells, in particular germ cells, is unknown. The aim of this study was to determine the presence of sialic acids as the final components of glycoconjugates, the main macroergic compound - ATP, to evaluate the generation of O2¯ in embryos of lobster (Misgurnus fossilis L.) under the influence of the antibiotic flurenizide. Studies have been performed on embryos of Misgurnus fossilis L. After fertilization, the zygotes were placed in Petri dishes with solutions of flurenizide in concentrations of 0.01; 0.05; 0.15; 1.0; 5.0; 15.0 mM, where allowed to develop. At the development stages, 2 blastomeres, 16 blastomeres, 64 blastomeres, VIII (256 blastomeres) and X divisions (1024 blastomeres) were sampled. In parallel, control studies were performed, where flureniside was not added to the samples. The content of sialic acids, ATP, superoxide anion radical was determined in the selected samples. We found that flureniside at the lowest concentration of 0.01 mM does not cause changes in the content of superoxide anion radical during early embryogenesis. The antibiotic in the maximum concentration causes changes in the content of free radical from the stage of development of 16 blastomeres to 1024 blastomeres, and from the stage of 64 blastomeres there is an increase in its number. Probably flurenizide at a concentration of 15.0 mM is the most reactive. It is known that flurenizide has antioxidant properties, but in its structure there are groups that have a toxic effect, which is most pronounced when exposed to high concentrations. In general, at the stage of development of 16 blastomeres there is a decrease in the amount of О2¯ under the influence of the studied antibiotic. At this time, the content of this free radical in the control increases, compared with other stages of development. Flureniside leads to an increase in the content of superoxide anion radical at development stage 2, 64 blastomeres and is particularly pronounced at concentrations from 0.05 to 15.0 mM at development stages 256 and 1024 blastomeres. 1024 blastomeres are the 10th stage of separation, where desynchronization occurs and the mitotic index decreases. Probably, the changes that take place at this stage of development are related to this. The antibiotic causes an increase in the content of sialic acids in the first stage of crushing (2 blastomeres). In step 16 of the blastomere, flureniside in low concentrations leads to a decrease in the content of sialic acids. However, already at the stage of separation of 64 and 256 blastomeres, the test substance in all concentrations causes a predominant decrease in the amount of sialic acids. At the last stage of synchronous crushing (1024 blastomeres) flurenizide in the maximum investigated concentration (15.0 mM) causes a significant accumulation of sialic acid content. Flureniside at concentrations of 0.15, 5.0 and 15.0 mМ causes a decrease in ATP content in loach embryos at the stage of development of 256 blastomeres by 28, 67 and 38 %, respectively. An increase in ATP content by 33 % occurs under the influence of flurenizide at a concentration of 1.0 mM. The ATP content also increases at the stage of development of embryos of 1024 blastomeres under the influence of flurenizide of all studied concentrations. Analysis of variance has shown that a significant contribution to the growth of ATP, sialic acid and superoxide anion radical, during the early embryogenesis of lobster embryos, is made by the factor of embryo development, while the factor of flureniside has a smaller contribution. Therefore, studies have shown that flurenizide causes increased generation of superoxide anion radical, decreased sialic acid content, as well as changes in ATP content in embryonic cells during early embryogenesis.