AbstractThis study was undertaken to investigate the possible antimutagenic effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on 3,2´‐dimethyl‐4‐aminobiphenyl (DMAB)‐induced mutagenicity, using the AmesSalmonella/mammalian microsome system. The addition of 100–250μg of BHT or 25–500μg of BHA/plate was found to inhibit DMAB‐induced mutagenicity inSalmonellastrains TA 98 and TA 100. In TA 100, the mutagenicity was further inhibited with the addition of S9 prepared from the livers of rats fed a 0.6% BHT diet as compared to S9 from the animals fed a diet containing no BHT.