In recent times interest has increased in the complementary medicine of cancer patients. Two herbal mixtures were prepared from 17 and 12 plants, respectively. The goal of this study was to examine the in vitro cytotoxic and cell cycle effects of the aqueous-ethanol extracts (Extract 1 and Extract 2) obtained by maceration of the mixtures. The two extracts investigated exhibited significant antiproliferative activity toward two human breast cancer cell lines (MDA-MB-361 and MDA-MB-453) and a human cervix carcinoma cell line (HeLa) with 50% inhibitory concentration (IC(50)) values ranging from 9.92 to 17.38 microL/mL. The extracts did not exert any significant cytotoxicity toward healthy human peripheral blood mononuclear cells. In vitro antitumor activities were accompanied by an important apoptotic fraction of all cell lines after treatment with the extracts. The amount of total phenols was similar in both extracts, whereas the concentration of total tannins was significantly higher in Extract 1. Extract 1 was also found to be a stronger free radical scavenger, with an IC(50) value of 13.4 microg/mL. Both extracts contained rosmarinic acid, while ursolic acid was identified in Extract 2.