Background: Using the plants to treat the diseases, which has increased around the world, does not have any side effects. This study aimed to examine the antimicrobial effects of Melissa officinalis L. essential oil and Nanocopper particles on growth inhibition of S.aureus (MRS).

Materials and Methods: In this experimental study, Inhibition zone diameter of the materials was measured using the Agar disk diffusion method. Different concentrations of Melissa officinalis L. essential oil and Nanocopper particles were prepared. Then, the antimicrobial activity of the materials 24 hour after the treatment was evaluated for Nanocopper particles in concentration of 100 and 500 ppm and essential oil 12.5% to 50%.

Results: Results of this study showed that Nanocopper particles does not have any inhibitory effect on S.aureus (MRS) growth 24 hour after the treatment. Inhibition zone diameter for different concentrations of Melissa officinalis L. oil was 19/91±0.13mm. Mixture of 500ppm Nanocopper particles and different concentrations of Melissa officinalis L. oil after 24 hour showed that mixture of the two substances does not have any synergic effect on growth inhibition of S.aureus (MRS).

Conclusion: Nanocopper particles and Melissa officinalis L. oil do not have any synergic effect on S.aureus (MRS) growth in vitro condition. This Melissa officinalis L. essential oil can be used as antimicrobial agent for inhibition of bacterial diseases in human.