Anacardic acid is the main constituent of Cashew Nut Shell Liquid. It has carboxyl and phenolic hidroxyl groups besides alkyl group. Methylation those groups give methyl esther of anacardic acid and methyl ether of anacardic acid. The assay of the three compounds shows that they are cytotoxic to L1210 leukemic cell in vitro. Methyl esther of anacardic acid citotoxicity is higher than that of methyl esther methyl ether of anacardic acid. The citotoxicity of the compounds relates to their polarity and reactivity of their functional group.