Freeze-dried fruits of two strawberry cultivars, Sweet Charlie and Carlsbad, and two blueberry cultivars, Tifblue and Premier, were sequentially extracted with hexane, 50% hexane/ethyl acetate, ethyl acetate, ethanol, and 80% acetone/water at ambient temperature. Solvents were then evaporated at 40° C. The extracts were tested against in vitro cultures of two aggressive cervical cancer cell lines (CaSki and SiHa) and two breast cancer cell lines with different requirements for estrogen (MCF-7 and T47-D). The metabolic activity of the cultures was assessed with MTS viability assay. The Ames assay for mutagenesis was used to evaluate the anticarcinogenic effects of phytochemicals with a 90% accuracy. Ethanol extracts from all four fruits strongly inhibited CaSki and SiHa cervical cancer cell lines and MCFF-7 and T47-D breast cancer cell lines. An unfractionated aqueous extract of raspberry and the ethanol extract of Premier blueberry significantly inhibited mutagenesis by both direct-acting and metabolically activated carcinogenesis.