Cocoa flavonoid, found in the high est concentrations in dark chocolate, exhibit antioxidative and cardioprotec tive properties, inhibit platelet activity, and activate endothelial nitric oxide syn thase. Although the exact mechanism is not clear, results from mechanistic and clinical studies suggest that the blood-pressure-lowering effects of dark chocolate may be due to activation of endothelial nitric oxide synthase, which results in arterial vasodilation.