Hypericum scabrum L. is an endemic medicinal plant with antimicrobial, anticancer and anti-inflammatory, antiviral effect. In this study, we aimed to investigate the cytotoxic effect of water and methanol extracts on different cancer cell lines such as osteosarcoma cancer, cervical cancer and prostate cancer. The data showed that the methanol extract had a highly effective cytotoxic effect on all three cell lines. Although water extract caused less cell loss than methanol extract, it was found that the cells were inhibited in all three cell lines. DU-145, which is the prostate cell line, was more effective in both extracts. As a result, the water and methanol extract of Hypericum scabrum L. have an anticancer effect on Saos-2, HeLa and DU-145 cells. There is a need for further and comprehensive studies by isolating the main active ingredient of this plant which is a candidate for drug of cancer in the future. Our study is expected to lead the studies in this direction.