Zinc oxide nanoparticles (ZnO NPs) have a multiple applications due to their special physico-chemical and antimicrobial properties. Moreover, they are inexpensive and less cytotoxic than others metal nanoparticles. The increasing use of the ZnO NPs in different sectors has raised concerns about their potential risks for the workers, consumers and environment. The posible toxic effects of different zinc oxide nanomaterials (G-ZnO, ZnO and ZnO:Mn) on the respiratory system and their irritant potential were evaluated. The antimicrobial activity of G-ZnO, ZnO and ZnO:Mn was analysed against Gram positive (methicillin-resistant S. aureus and vancomycinresistant E. faecium) and Gram negative (A. baumannii and P. aeruginosa) bacteria.