Expression levels of GST-P examined by immunohistochemical analysis in the four groups (G1, G2, G3 and G4) demonstrated that no positive area was observed in the control livers and that administration of DEN induced GST-P-positive area (G2), which was significantly inhibited by the treatment with both low (0.07%, G3) and high (0.35%, G4) concentrations of geraniol, revealing no significant difference between G3 and G4. ***P < 0.001. Bars express 200 µm. Arrows indicate representative GST-P-positive area. DEN, diethylnitrosamine; GST-P, glutathione S transferase-P.