Yarrow essential oil is used in complementary and alternative therapy for several diseases. Biological effects of essential oils span various cells and microorganisms. The aim of this study was to investigate the effects of different concentrations of the essential oil obtained from the yarrow plant (Achillea millefolium) on HeLa (CCL-2) cells. The components of the essential oil were studied by means of GC-MS analysis. Out of 10 determined compounds in the essential oil; 1,8-Cineole, Camphor, Beta-eudesmol and Camphene were found to be higher than others; and their biological effects were depicted with Ingeniuty Pathway Analysis (IPA) analysis. Moreover, cell cycle and proliferation tests were conducted on HeLa cells where yarrow plant's essential oil was used. When extracted yarrow oil applied on HeLA Cells, apoptotic effects had been determined, furthermore proliferation of these cells decreased. In addition, activation of cell cycle control points was observed . Essential oil components could arrest the development of HeLa cells due to induction of cellular damage control mechanisms. In conclusion, we propose that the essential oil had a more repressive effect on HeLa cells, decreases their proliferation and prevented the increase in the number of cells.