Abstract: The invention relates to polymers comprising carbohydrate ligands and moieties, respectively, that bind to carbohydrate-binding proteins (CBPs), as well as to these carbohydrate ligands, and to their use in diagnosis and therapy of diseases that are associated with CBP-mediated cytotoxicity, agglutinatination, or immune complex deposit formation. In particular, the invention relates to polymers comprising a multitude of said carbohydrate ligands and moieties, respectively, mimicking carbohydrates that are bound by CBPs which belong to the group of (i) bacterial exotoxins, (ii) agglutinins, and (iii) immune complex deposit-forming immunoglobulins. Furthermore, the invention relates to the use of these polymers and carbohydrate ligands and moieties respectively, in diagnosis as well as for the treatment of diseases that are associated with CBP-mediated cytotoxicity, agglutinatination, or immune complex deposit formation. In one embodiment, the polymer is polylysine.