We investigated effects of methanol extract of Aloe vera on anticancer drugs(cisplatin, mitomycin C, 5-fluorouracil)-induced growth inhibition in p388, L1210, HCT-15, SK-HepG-1 as cancer cell lines and mouse splenocytes as a normal cell by MTT assay, respectively. We also examined the effects of aloe extract and mitomycin C on the mitogen(Con, A, LPS)-induced splenocyte proliferation. Aloe extract(0.25 mg/m , 1.25 mg/m , 2.5 mg/m , 5.0 mg/m ) showed dose-dependently selective cytotoxicity against the cancer cell lines. In contrast, Aloe extract increased the growth and proliferation of the normal mouse splenocytes. The combination of aloe extract with anticancer drugs showed an additive effect for the cytotoxicity against cancer cell lines. However, that combination reduced clealy the anticancer drugs-induced toxicity against the normal mouse splenocytes.