Hypericum species are used in different folk medicines and screened for their biological activity including cancer. We, therefore, evaluated the possible cytotoxic/apoptotic and genotoxic activities of Hypericum adenotrichum Spach. and Hypericum olympicum L. Antigrowth effect was screened in human lung cancer cell lines (A549 and PC3) by the ATP viability assay, while genotoxic activity was performed using the Comet assay. Histological and biochemical methods were utilized to elucidate the cell death mode. The results indicate that the crude methanol extracts of H. olympicum L. and H. adenotrichum have both antigrowth/cytotoxic and genotoxic activities on these cells in a dose dependent manner. These extracts clearly induced apoptosis in PC3 lung cancer cell lines. In this study, we report for the first time that the H. olympicum and H. adenotrichum exhibits potential cytotoxic and genotoxic activities in lung cancer cells as well as the apoptosis-inducing roles through DNA damage in PC3 cells.