Reactive oxygen species (ROS) are common metabolites produced during meiotic maturation of germ cells and embryonic development, and have physiological significance. However, their increased generation is extremely harmful. The work is devoted to studying the effect of quercetin on oocyte meiotic maturation, as well as cumulus cell viability and death in mice under oxidative stress conditions induced by lipopolysaccharide in vitro. It was established that at doses of 5 and 10 μmol/l, the antioxidant has a positive effect on О.А. Кондрацька, В.В. Мешко, Р.І. Янчій 66 the ability of oocytes to reach the metaphase I and II stages. However, increasing the concentration of quercetin to 20 μmol revealed its toxic effect. The protective effect of quercetin (10 μmol/l) on the viability of cumulus cells was also shown, which occurred due to a decrease in their apoptotic and necrotic death. Thus, the effective doses at which quercetin exerts a cytoprotective effect on the meiotic maturation of murine oocytes and cumulus cell viability under lipopolysaccharide- induced oxidative stress in vitro have been established. The obtained results indicate the promise of using quercetin to correct the negative effects caused by the action of LPS on oocytes, which can significantly increase the effectiveness of assisted reproductive technologies.