Natural compounds are extensively used in the treatment of various diseases. Regular consumption of polyphenols plays an important role in the protection of health by reducing the risk of degenerative diseases, including cancer. The evaluation of the cytotoxic effect of the newly obtained multifruit polyphenolic preparation (composed of seven fruit) on T47D and MCF-7 breast cancer cells and MCF-12A normal cells. The PP was produced on the basis of combined ultrafiltrates obtained from chokeberry, raspberry, wild strawberry, apricot, peach, bilberry, and cranberry. The experiments were performed using human mammary gland cancer cell lines T47D (ductal cancer) and MCF-7 (adenocarcinoma) and normal breast cell line MCF-12A. hromatographic techniques confirmed the highest contribution of cyanidin 3-O-glucoside, p-coumaroyl glucoside and chlorogenic acid in the PP. The PP exhibited dose-dependent cytotoxic effects towards MCF-7 and T47D cancer cell lines (IC50 = 1.2 μg. cm-3) and MCF-12A cells (IC50 = 0.6 μg. cm-3). The MTT cytotoxicity assay and microscopic observations confirmed the cytopathic effect of the PP on cell lines. It is supposed that berry polyphenols interfered with estrogen receptors leading to changes in the production of paracrine growth factors and therefore, PP was less cytotoxic towards the MCF-7 and T47D cell lines than against the MCF-12A cell line.