Citral, trans-cinnamaldehyde, (−)-perillaldehyde, (−)-citronellal, eugenol and carvacrol were tested for their influence on microbial count in air by vaporizing with an air washer. The highest antibacterial activity was observed when (−)-perillaldehyde was sprayed. The average reduce of germ count was 53%. On the other hand, the antimicrobial activity of eugenol was the lowest of these six compounds. The average reduction of germ count was 13%. When water without volatile compounds was sprayed, the colony forming units increased. These results suggest the utility of selected aroma-compounds for the control of bacteria in the room.