The in vitro action of some total aqueous and hydroalcoholic extracts and of their concentrate or permeate fractions, separated by membranary micro- and ultrafiltrations of the primary homogenates, obtained from Helleborus purpurascens ethnomedicinal plant, upon the cell protein biosynthesis, proliferation, viability and development of the HeLa cancerous cells cultures was investigated. The significant proteinsynthesis alteration, protein dynamics modification, decrease of total cell number, cell viability diminution, inhibitory impact upon the cell cultures development, during studied evolution period, suggest the behaviour of these polyphenolic hellebore extracts as in vitro active cytostatic and cytotoxic agents. Our preliminary characterization of these vegetal biopreparations as protein, mitotic, growth inhibitors offers the informational background for further investigations, on many other cancerous and normal cell lines and adequate experimental models to in vitro prescreening, as well as for their introduction in the in vivo antitumoral screening program on different experimental tumoral systems.