Resveratrol is a phytoalexin that is found in a few edible food materials such as grape skins, pea-nuts and red wine. Numerous reports exists in the literature suggesting that dietary resveratrol may act as an antioxidant, promotes nitric oxide production, inhibits platelet aggregation and increases high-density lipoprotein cholesterol, and subsequently may serve as a cardio-protective agent. Recent reports demonstrated that resveratrol can function as a cancer chemopreventive agent, exhibiting anti-inflammatory, neuroprotective, anti-ageing and antiviral properties. However, most of these effects are yet to be confirmed in humans. In the only clinical trial, high doses of special proprietary formulation has demonstrated blood sugar-lowering effects of resveratrol in type 2 diabetes mellitus. As with many polyphenols, resveratrol is reasonably well absorbed but has low bioavailability. It is metabolized by hydroxylation, glucuronidation, sulfation and hydrogenation. We reviewed the published literature and reports to consolidate information available on the biological activity of resveratrol using electronic databases as well as handpicked articles to summarize the biological effects of resveratrol and its clinical benefits against human diseases.