Objective: To study if demethoxyviridine (DMV) and its analogue 1-a- hydroxy-demethoxyviridine (1--hydroxy- DMV) can protect against liver cancer induced by diethylnitrosamine (DEN) and 2- acetylaminofluorene (2-AAF) in two-month-old male Spraque-Dawley rats. Methods: Animals were divided into 10 groups: control, or treated with olive oil, DMSO, DMV, 1--hydroxy-DMV, DEN, 2-AAF, DEN+2- AAF, DEN+2-AAF+DMV and DEN+2-AAF+1-- hydroxy-DMV. Liver tissue slides were evaluated histopathologically with H&E staining and immunohistochemically for Ha-Ras, GST-p and Cx32 proteins. Liver microsomes were prepared from rats and the expression of CYP1A2 enzymes was determined with the Western blot technique at the end of the study. Results: No differences were observed between control (53.28±2.85 ng), olive oil (46.71±2.43 ng) and DMSO (40.85±1.22 ng) groups in terms of CYP1A2 expression. However, the least CYP1A2 expression was found in group DMV (40.85±1.22 ng) and significant in groups 1- a-hydroxy DMV (28.42±1.89 ng), DEN + 2-AAF + 1- a-hydroxy DMV (28.14±2.44 ng) and significantly decreasing in groups DEN (19.14±3.67 ng), 2-AAF (11.28±2.77 ng), DEN + 2-AAF (15.57±4.48 ng) as well as DEN + 2-AAF + DMV (20.14±3.82 ng). No histological differences were observed for olive oil, DMSO, DMV and induced groups. A prenoplastic focus was found in DEN+2-AAF treated group carried out histopathologically with H&E staining. Immunohistochemistry revealed increased amounts (54) of Ha-Ras and GST-p proteins in the DEN+2-AAF group but normal amounts (4) in the DEN+2-AAF+DMV and DEN+2-AAF+1-(-hydroxy-DMV treated groups. However, Cx32 protein levels did not change in any groups. Conclusions: Fungi metabolites appeared to protect against liver cancer induced by DEN, 2-AAF and DEN+2-AAF, but further studies are needed to fully determine the time course of this protective effect.