Treatments on the cardboard that can make it anti-mildew or anti-bacterial, at least at the level of the exposed surface towards the packaged product, in order to prolong its shelf life and ensure its good preservation, are in many cases based on the use of metals or oxides. Nevertheless, the use of natural substances is better for obvious reasons related to the better compatibility with human organism and for the lower impact onto environment. In nature, chitin is in the form of crystalline structures with a high structural order called \"nanofibrilsâ€. These crystallites have an average size equal to about 240x7x5 nm, while the term fibril indicates a thin and needle-like structure.rnThe solubility, biodegradability and antimicrobial properties of chitin, as for chitosan, depend on the extraction source of the polysaccharide and on the degree of acetylation of the glucosamine units, as well as on their arrangement along the polymeric chain.rnIn the present paper, presenting the results about a project funded by Bank Foundation Cassa di Risparmio di Lucca and developed in collaboration with Lucense research center about cellulosic products, slightly acidic aqueous solutions containing chitin and chitosan were prepared to obtain films by means of solvent casting to simulate the thin layer to be deposited on the cardboard. Mechanical properties of the films have been studied. The best formulations were then used to treat virgin and recycled paper with different devices. Several series of samples have been characterized by evaluating the anti-microbial properties with the use of different types of tests.