Cinnamic aldehyde and its complex with beta-cyclodextrin were added (5%) to the title films, tested then for mech. and antimicrobial properties. The tests did not show any significant deterioration of the mech. properties of the modified films. Cinnamic aldehyde-doped PE-LD films inhibited the growth of both Gram-pos. bacteria (S. aureus) and Gram-neg. bacteria (E. coli) by 99.99% and 99.81%. resp., whereas beta-cyclodextrin complex-doped films by 99.99% for both strains. The PLA films inhibited only the growth of Gram-pos. bacteria (S. aureus) by 96.45%.