Using the light microscopy and MTT cytotoxicity assay the pronounced cytotoxic effect of n-butanol partitioned phytochemicals from Tanacetum vulgare L. flowers (PhTvF) on viability of human cervical adenocarcinoma HeLa cells has been elucidated. The treatment of HeLa cells with PhTvF for 48 h or 72 h led to changes in cell morphology that had an apoptotic character of cell death. The viability of PhTvF (0.2 mg/ml) exposed HeLa cell for 48 h and 72 h decreased up to 63% (p≤0.05) and to 48% (p=0.01), respectively. The PhTvF dissolved in 0.9% NaCl as vehicle solvent reviled IC50~0.1–0.2 mg/ml for HeLa cells. We have concluded that PhTvF exhibit tumor preventing properties in vitro and can be considered as the promising substances for development of a new preparation for antineoplastic therapies. The mechanism and possible leader compound of PhTvF cytotoxicity are now under investigation.