Novel agents exhibiting anti-biofilm formation activity while being non-cytotoxic are provided, as well as methods of using the same, either per se or conjugated to a polymer, for preventing and/or reducing the formation of microbial biofilms and/or for disrupting microbial biofilms. The novel agents described herein include thiazolidine-2,4-diones (TZDs), pyrrolidine -2, 5- diones (PYDs), imidazolidine-2, 4 -diones or oxazolidine-2,4-diones, substituted by an alkylidene having 7-20 carbon atoms in its backbone chain.