The study of polyphenolic extracts from skins, seeds, grape pomace and lees is justified by the huge amount of information from specialized literature, drawing attention to the many pharmacological effects of these biomolecules. The concentrated vegetal extracts obtained from seeds, skins, grape pomace and lees (yeast deposit after fermentation) were characterized according to their content of total polyphenols, anthocyanins, dry matter, ash and pH. The biological material used in the in vitro testing experiments in order to study cytostatic and cytotoxic effects were stabilized cultures of HeLa cancer cells, uncontaminated with mycoplasma and derived from a human uterine cervix carcinoma. Another action of the cytostatic substances could be exerted upon the cell proliferation process. The cell division process of the HeLa cell cultures treated with seeds by-product showed remarkable quantitative changes. The study has also evidenced a great number of dead cells in the composition of the treated HeLa cell cultures, their existence pointing out that the bioactive agent induced a major decrease of the cells viability. The obtained results in the context of the complex evaluation of the in vitro antitumoral property of the extracts, obtained from seeds, skins, grape pomace and wine lees from the ‘Arcaş’ grape variety, on HeLa cells cultures, have demonstrated the significant cytostatic and cytotoxic potential of the seeds polyphenolic biopreparate. The results obtained show that polyphenolic extracts from Vitis vinifera seeds act as cytostatic and cytotoxic agents.