OBJECTIVE: Cancer is a formidable problem for global health, and the increasing burden necessitates the search for new and alternative treatments and/or approaches. For this reason, any approach to cancer treatment is extremely valuable. Recently, there has been increasing interest in the use of plant-derived compounds in the treatment of cancer. Many studies have shown that many of the best-selling anti-cancer drugs are of plant origin. Based on this, the cytotoxic potential of two extracts [C. fenzlii leaf extract (CFL) and C. fenzlii capitula extract (CFC)] from Centaurea fenzlii, a plant species endemic to Turkey, were tested in two different cancer cell lines (DLD1 and ARH77) and a healthy cell line (HUVEC). MATERIALS AND METHODS: Cytotoxic effects of the extracts were determined by MTT assay, changes in the mRNA expressions of the apoptotic genes (apaf, bax, bcl2, bcl2l11, casp3, gadd45a and hrk) were determined via the qRT-PCR technique, and the caspase3 enzyme activity was determined. In addition, the capacities of the extracts against invasion and migration were also evaluated. The chemical content and phenolic composition were evaluated via the gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) techniques. RESULTS: As a result, the extracts showed a selective cytotoxic effect in all the cancer cell lines examined, especially the DLD1 colorectal cell line. In addition, it has been determined that the extracts inhibit the invasion and migration of cells. CONCLUSIONS: The results of the study reveal that C. fenzlii, which has been found to have acceptable anti-cancer effects, should be investigated with more comprehensive studies.