The effects of five naturally occurring antioxidants, beta-carotene (BC), vitamin C (VC), vitamin E (VE), ellagic acid (EA) and epigallocatechin gallate (EGCG) on 8-hydroxydeoxyguanosine (8-OH-dG) formation by 2-nitropropane (2-NP), a hepatocarcinogen in rats, were studied. Four days oral administration of VE (100 mg/kg BW/day) or EA (100 mg/kg BW/day) significantly inhibited 8-OH-dG formation in the liver nuclear DNA of male F-344 rats injected with 2-NP (100 mg/kg BW, i.p., killed 6 h later). The same treatment with EGCG (100 mg/kg BW/day) showed slight, but not significant, inhibition. In contrast, 4 days' oral administration of BC (100 mg/kg BW/day) or VC (300 mg/kg BW/day) and 3 weeks' feeding of the two (either at 0.5% in the diet) did not produce any inhibitory effects on 8-OH-dG formation. Thus, it is expected that VE and EA may have anticarcinogenic effects towards 2-NP.