We have supposed, that environmental contaminants, plants and plant substances can affect basic ovarian functions, and that plants, plant substances and hormones may affect basic ovarian functions, and that plants, herbal substances, and hormones may modify the potentially adverse effects of environmental contaminants on basic ovarian functions. The aim of the dissertation was to determine the influence of environmental contaminants (benzene, toluene and xylene), plants (tribulus terrestris, chia, fennel, ginkgo, flaxseed, yucca, rooibos, vitex, buckwheat), plant ingredients (quercetin, daizdein, diosgenin, apigens, rutins) and hormones (ghrelin, leptin, FSH) on viability, proliferation, apoptosis and secretory activity by cultured ovarian cells of bovine, porcine, pregnant and non-pregnant cats, horse and humans in vitro. Granulosa cells and ovarian fragments were cultured with additions alone (1, 10 and 100 µg.ml-1), in combination with contaminants (20 µg.ml-1) or in three contaminant concentrations (0.02, 0.2 and 2 µg / ml). µg.ml-1) and plant supplement (1 µg.ml-1). Proliferation and apoptosis were detected by immunocytochemical analysis using PCNA and BAX markers. Secretory activity (secretion of estradiol, progesterone, testosterone, prostaglandin F, IGF-I and oxytocin) of ovarian granulosa cells was determined by ELISA, EIA and RIA. We have observed evidence of the direct effect of environmental contaminants, plants, plant substances and hormones on the basic functions of granulosa cells - viability, proliferation, apoptosis, release of steroid and peptide hormones, also, that xylene affect differently the ovarian function of pregnant and non-pregnant cats. We have found that plants, herbal substances and hormones have the ability to modify the negative effects of environmental contaminants on the basic ovarian cell functions. On the base of these obtained results, we can assume, that environmental contaminants may negatively affect female reproductive systems and that selected plants, plant substances, and hormones can be used as regulators of some ovarian functions. In addition, we found a different effect of xylene on hormone release by pregnant and non-pregnant cat ovaries. We also found that selected plants, herbal substances and hormones can modify the effect of contaminants on ovarian function, and some of them can be used as a natural prevention against the negative effects of benzene, toluene and xylene on reproduction.