BackgroundThis study aims to clinically verify the effects of myrtle essential oil, which has non-irritation, non-toxicity, and non-sensitivity characteristics among natural materials, by applying the oil to acne skin of Korean women, with special emphasis on a development of natural substances with a high safety to relieve acne and minimize skin irritation.MethodsAfter a homogeneity test was conducted targeting 20 Korean women with acne skin, who have met the primary and the secondary clinical selection criteria, the subjects were divided into the treatment group with myrtle essential oil applied (the experimental group) and the no-treatment group with no myrtle essential oil applied (the control group) to use provided cosmetics every morning and evening for 6 weeks. To precisely check the effects of the myrtle substances, the provided cosmetics are made with only a difference in the presence or absence of added myrtle substances, leaving all other substances equal.ResultsThe acne grades significantly decreased in the experimental group with myrtle applied, with the pore index (outstanding pores, large pores, blackheads), the erythema index, the sebum index, and the desquamation index also decreased in the group. Lastly, the microorganism index decreased considerably in the experimental group, showing all evaluation indicators related to acne improved in the experimental group in a statistically significant manner. On the other hand, the acne grades a little decreased in the control group with no myrtle applied, but with no statistical significance, while the pore index (outstanding pores, large pores, blackheads), the erythema index, the sebum index, and the desquamation index rather increased to some extent. In addition, the microorganism index decreased in the control group, but with a smaller volume of changes than that in the experimental group.ConclusionThis study has clinically proved that myrtle essential oil has effects for convergence, reduction in erythema, removal of sebum and dead skin cells, and antibacterial activity on the facial skin of Korean women. Especially, this study confirmed that myrtle essential oil is a safe, skin-soothing substance effective for treating acne by showing the oil reduced the number of erythema.Trial registration-Name of the registry: Institutional Review Board of Korea Institute of Dermatological Sciences-Trial registration number 1-70005239-AB-N-01-2018-KIDS-AHA043-HR-01-Date of registration: March 2, 2018.