Results: Vacuolization were observed extensively in hepatic cells in the model group after 6 weeks and 12 weeks of high-fat diet. It is demonstrated that rats fed with high-cholesterol food are indeed fatty liver models. Western blot showed that the level of arginase II increase in the liver of model group rats as compared to the control group. Furthermore, the level of arginase was higher in liver samples obtained from model rats that were 12 weeks on a fat diet as compared to rats that were only 6 weeks on the same diets. Conclusion: The level of arginase II was altered in the progress of non-alcoholic steatohepatitis in rats suggesting that arginase II is putative biomarkers and may represent new targets in the development of therapeutic strategies against fatty liver disease hepatic fibrosis and cirrhosis.