Curcumin, a pigment responsible for the yellow color of curry, has been shown to be an anti-inflammation agent, an antioxidant and an antipromoter. 8-Hydroxydeoxyguanosine (8-OH-dG), an oxidized nucleoside, may be responsible for a genetic event of tumor promotion in carcinogenesis. 8-OH-dG can be detected selectively and sensitively at the fmol level by HPLC-electrochemical detection at an applied potential of +0.8 V versus Ag/AgCl. Phorbol-12-myristate-13-acetate (PMA), a potent tumor promoter, induces lipid peroxidation and 8-OH-dG formation. Curcumin can strongly scavenge the hydroxyl radical (OH.) to prevent 8-OH-dG formation from dG (deoxyguanosine) in vitro and reduce the production of PMA-induced lipid peroxidation and 8-OH-dG in mouse fibroblast cells. These results suggest that curcumin inhibits the PMA-induced tumor promotion by functioning as an OH. radical scavenger to prevent 8-OH-dG formation within the DNA molecule.