The influence of adamantane derivatives (remantadine and amantadine) on the surface charge of lipid bilayer when they are adsorbed on an artificially formed bilayer lipid membrane (BLM) was studied. The presence of the final number of binding centres on the BLM surface for remantadine and amantadine molecules and the cooperative nature of interaction of these compounds with the lipid bilayer were demonstrated. The features of interaction of influenza virus proteins isolated from the virion--M protein and a mixture of surface glycoproteins--were studied. Both antiviral compounds were shown to reduce markedly M protein adsorption on the lipid bilayer and to affect negligibly the sorption properties of the surface glycoproteins. Remantadine molecules interact directly with M protein molecules reducing their hydrophobic properties and, thereby, reducing the affinity of this viral polypeptide to lipid bilayer.