Antitumoral effect of ethanolic extract of propolis (EEP) was demonstrated in mature mice-bearing Ehrlich carcinoma. Survival rate after EEP treatment was compared to that of bleomycin, given alone or in combination every two days for 36 days and followed up for 14 additional days. The survival rate at 50 days was 55% after EEP and 40% after bleomycin, while all the mice-treated with EEP + bleomycin combination demonstrated shorter survival than the controls. It is concluded that while the in vivo activity of bleomycin is reduced in the presence of cytochrome-C-reductase inhibitors (like some of the EEP components are), the antitumoral property of EEP in the tumored animal model studied is significant and lasting.