this study analyzed the chemical composition of ogeo and its effects on growth, viability, antrum formation and mrna expression for superoxide dismutase (sod), catalase (cat), glutathione peroxidase (gpx) and peroxiredoxin 6 (prdx6) in bovine secondary follicles cultured in vitro. the follicles were cultured in tcm-199+ alone or supplemented with 0.125, 0.25 and 0.50% ogeo for 18 days. follicle diameters, viability, antrum formation and the levels of mrna for sod, cat, gpx1 and prdx6 in cultured follicles were evaluated. the results showed that the main components of ogeo were eugenol and 1.8-cineol. the follicles cultured with ogeo maintained morphology, viability and growth similar to the control group. interestingly, follicles cultured with 0.5% or 0.25% ogeo had, respectively, higher levels of mrnas for prdx6 and cat than those cultured in control medium. in conclusion, ogeo increases mrna expression for prdx6 and cat in bovine secondary follicles cultured in vitro.