The effects of the anticancer drug irinotecan combined with ethanolic extract of propolis (EEP), a water-soluble derivate of propolis (WSDP), quercetin and naringin on the growth of Ehrlich ascites tumor (EAT) and the life span of tumor-bearing Swiss albino mice were studied. Test components were given to mice intraperitoneally (i.p.) at doses of 100mg kg(-1) for three consecutive days before the i.p. injection of EAT cells (1x10(6)). Irinotecan was administered i.p. at dose of 50mg kg(-1) on days 1, 13, and 19 after tumor cell inoculation. The results clearly demonstrate the synergistic action of irinotecan and EEP on survival time. These results suggest that clinical trials using a propolis preparation EEP combined with irinotecan may be beneficial in maximizing antitumor activity and minimizing post-chemotherapeutic reactions to the cytostatic drug.