L-519 is a phenolic compound. In this study, L-519 was found to inhibit the mutageniclty of benzo(a)pyrene [B(a)P] in Salmonella Typhimurium TA 97 and TA 100 and inhibit the cytochrome P-450 mediated metabolism of B(a)P. It also inhibited the epidermal ODC activity induced by croton oil. L-519 also decreased the lipid peroxidation induced by FeSO₄ and Cysteine in rat liver microsome system. Our results demonstrated that 1.-519 exhibited anti-mutagenicity, anti-initiation as well as anti-promotion activities.