The ability of anthocyanins to permeate the gastric mucosa can be suggested as a possible explanation of the fast kinetics of plasma appearance of anthocyanins in rats and humans. This paper presents an in vivo experiment aimed to prove the involvement of the stomach in the absorption of grape anthocyanins in rats. The required analytical selectivity and sensitivity was achieved by high-performance liquid chromatography, diode array detection and mass spectrometry. Malvidin 3-glucoside appeared in both portal and systemic plasma after only 6 min. The average concentrations measured in portal and systemic plasma were 0.650+/-0.162 microM and 0.234+/-0.083 microM (mean+/-S.E.M.), respectively.