<p>ABSTRACT<br />Objective: Essential oils with antimicrobial and antioxidant activities have gained importance. This study was conducted to investigate the genotoxic<br />potential of the essential oil of Origanum compactum.<br />Methods: Micronucleus test and proliferation index (PI) were used to evaluate the genotoxic effect of the essential oil of O. compactum on human<br />lymphocytes.<br />Results: The results demonstrated that the PI values were influenced by the tested essential oil. An increase in concentration of essential oil also<br />caused the appearance of micronuclei.<br />Conclusion: The results of the present work suggest that O. compactum essential oil exhibited genotoxic activity at higher concentration. Further<br />studies are necessary to confirm these findings.<br />Keywords: Origanum compactum, Human lymphocytes, Proliferation index, Micronucleus test.</p>