Considerable epidemiological evidence suggests a link between the consumption of diets rich in fruits and vegetables and a decreased risk of cardiovascular disease and cancers. Anthocyanins have received attention as important dietary constituents that may provide health benefits and contribute antioxidant capacity beyond that provided by essential micronutrients such as ascorbate, tocopherols, and selenium. The emergence of renewed interest by industrial countries in traditional herbal medicines and the development of 'functional foods' are stimulating the need for more information regarding the bioavailability and efficacy of plant polyphenols. Flavonoids represent a numerous group of secondary plant metabolites based on the structure of a pyran ring flanked by two or more phenyl rings and varying subtly in the degree of unsaturation and the pattern of hydroxylation or methylation. Flavonoids also vary in the type of sugar attached or the degree of polymerization. Anthocyanins, potent flavonoid antioxidants widely distributed in fruits, vegetables and red wines, normally occur in nature as glycosides, a form not usually considered as bioavailable. We have examined the bioavailability and pharmacokinetics of anthocyanins in humans. Anthocyanins were detected as glycosides in both plasma and urine samples. The elimination of plasma anthocyanins appeared to follow first-order kinetics and most anthocyanin compounds were excreted in urine within 4 h after feeding. The current findings appear to refute assumptions that anthocyanins are not absorbed in their unchanged glycosylated forms in humans.