A phytoalexin derived from grapes and other food products with antioxidant and potential chemopreventive activities. Resveratrol induces phase II drug-metabolizing enzymes (anti-initiation activity); mediates anti-inflammatory effects and inhibits cyclooxygenase and hydroperoxidase functions (anti-promotion activity); and induces promyelocytic leukemia cell differentiation (anti-progression activity), thereby exhibiting activities in three major steps of carcinogenesis. This agent may inhibit TNF-induced activation of NF-kappaB in a dose- and time-dependent manner.