AIM: To investigate if iron deposition and fat accumulation in the liver play a pathogenetic role in dimethylnitrosamine (DMN)-induced liver fibrosis in rat.METHODS: Thirty rats were treated with DMN at does consecutive days of 10 μL/kg daily, i.p., for 3 consecutive day each week for 4 wk. Rats (n = 30) were sacrificed on the first day (model group A) and 21st d (model group B) after cessation of DMN injection. The control group (n = 10) received an equivalent amount of saline. Liver tissues were stained with hematoxylin & eosin (HE) and Masson and Prussian blue assay and oberserved under electron microscopy. Serum alanine aminotransferase (ALT)and liver tissue hydroxyproline (Hyp) content were tested.RESULTS: The liver fibrosis did not automaticallyreverse, which was similar to previous reports, the perilobular deposition of iron accompanied with collagen showed marked characteristics at both the first and 21st d after cessation of DMN injection. However, fat accumulation in hepatocytes occurred only at the 21st d after cessation of DMN injection.CONCLUSION: Iron deposition and fat accumulation may play important roles in pathological changes in DMN-induced rat liver fibrosis. The detailed mechanisms of these characteristics need further research.