Pathogenic bacteria must stably colonize mucosal surface to initiate the infectious process. A growing body of evidence indicates that bacteria attach to tissue surface by specific interactions between molecules of recognition (receptors) on host cell surface and adhesive molecules (adhesins) on the surfaces of the bacteria. One of the goals in the studies of bacterial adherence mechanisms is the eventual development of measures to prevent the adhesion of harmful bacteria to mucosal surfaces before the microorganism can produce tissue damage. In this paper we describe recent studies on the possibility to use in therapy either purified adhesins or receptors to block receptors and ligands respectively. We also describe recent studies on the development of antiadhesive vaccines, composed of purified ligands, to elicit local immune responses, resulting in the secretion of antibodies that cover the bacterial adhesins and thereby prevent attachment.