We investigated that the extract of Aloe vera L. and its fractions exert antimutagenic activity against Salmonella typhimurium TA98 and TA100, and antileukemic effect against K562 human leukemia cell line. The aqueous ethanolic extract of A. vera L. was revealed to have antimutagenic effect on the AF-2 (2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide) in Salmonella mutation assay. Among the three fractions (fractions A, B and C) separated by silica gel chromatography, fraction C $(50;{mu}g/plate)$ exhibited the greatest antimutagenic effect on the AF-2 with inhibition rate of 84 and 90% in Salmonella typhimurium TA98 and TA100, respectively. The fraction C $(500;{mu}g/ml)$ inhibited the growth of K562 human leukemia cell line by 93% in MTT assay. However, the components of A. vera L. did not exhibit cytotoxic effect against MDBK bovine normal kidney in MTT assay.