Respiratory tract infection by Pseudomomas aeruginosa may be life-threatening for intensive care patients and patients with cystic fibrosis (CF). The colonization of airways can be facilitated by bacterial lectins (carbohydrate-binding proteins) that attach bacteria to the glycoconjugates of the mucosa. We show in this paper that the fucose-specific lectin P. aeruginosa agglutinin II (PAII) produced by these bacteria can, in addition to facilitating bacterial adhesion, arrest ciliary beating in human airways in vitro. This inhibitory effect of the lectin can be abolished by preincubating PAII with its specific sugar, fucose. Furthermore, ciliary beating is completely restored by addition of fucose 2 h after administration of PAII to cell cultures. Therefore, adding a simple monosaccharide to nebulizers may improve the management of P. aeruginosa infection by abrogating the effect of PAII on ciliary beating, thus restoring part of the nonspecific pulmonary defense mechanisms of the airways.