The aim of our study was to examine the direct influence of plant polyphenol resveratrol and oil-related environmental contaminant benzene on ovarian hormone release, as well as the ability of resveratrol to prevent the effect of benzene. Porcine ovarian granulosa cells were cultured with and without resveratrol (0, 1,10 or 100 ug/ml) alone or in combination with 0.1% benzene. The release of progesterone, oxytocin and prostaglandin F was measured by enzyme immunoassay (EIA). Benzene promoted the release of progesterone, oxytocin and prostaglandin F. Resveratrol, when given alone, stimulated both progesterone and prostaglandin F, but not the oxytocin output. Moreover, resveratrol prevented and even inverted the stimulatory action of benzene on all analysed hormones. These observations demonstrate the direct influence of both benzene and resveratrol on porcine ovarian hormone release, as well as the ability of resveratrol to prevent the benzene action on the ovary.