Resveratrol, found in grapes, is a phytoalexin with antioxidative activity. The compound (100 and 200 microM) inhibited the proliferation of hepatoma cells, although this phytoalexin exerted little influence up to 50 microM. Resveratrol, however, suppressed the invasion of the hepatoma cells even at a concentration of 25 microM. Sera from rats orally given resveratrol restrained only the invasion of AH109A cells. Resveratrol and resveratrol-loaded rat serum suppressed reactive oxygen species-potentiated invasive capacity. These results suggest that the anti-invasive activity of resveratrol is independent of the anti-proliferative activity, and that the antioxidative property of resveratrol may be involved in its anti-invasive action.