Background: Taiwan has entered an aged society, and the incidence of chronic diseases such as obesity and metabolic syndrome has greatly increased with aging. Rice bran, which contributes about 10% of whole grain weight, is a by-product of the rice milling process. In Taiwan, there are 110,000-140,000 tons rice bran can be produced because of milling process, however, most of rice bran is used as the animal feeding or discarded as the agricultural waste. The utilization of agricultural byproducts or waste including rice bran is the recent trend for reducing the environmental burden and save resources. Previous studies indicated that the water extract of fermented rice bran (FRB-WE) effectively enhanced the nutritional values such as total phenolic contents. However, the ameliorated effect of FRB-WE on non-alcoholic fatty liver disease (NAFLD) was still controversial. The reasons may include the differences of fermentation processes, bacteria species and animal models. Therefore, the purpose of this study was to investigate the protective effects of FRB-WE on liver damage in old rats fed with high fat (HF) diet. Materials and methods: Rice bran (YuanShun Ltd., Yunlin County, Taiwan) was fermented with Aspergillus kawachii and FRB-WE was produced based on the previous study (Shirakawa et al., 2016). Forty-four week-old male Sprague–Dawley rats were randomly divided into four groups (7 rats/group), including normal control (NC) group (normal diet), HF group (HF diet; 60% of total calories from fat), HF+1% FRB group (HF diet+1% FRB-WE wt/wt) and HF+5% FRB group (HF diet+5% FRB-WE wt/wt). Body weights, liver function (AST and ALT activities), plasma leptin level, liver cytokine levels and liver histopathological changes were analyzed after 8 weeks-feeding. Results: The antioxidant ability of FRB-WE was 6.4 times of water extract made from non-fermented rice bran (Table 1). Body weight of HF group was significantly higher than that of NC group. However, body weights of FRB treatment groups were lower than HF group (Fig. 1). There were no significant differences among all groups in plasma AST and ALT activities (Fig. 2). Compared to NC group, plasma leptin level was significantly increased in HF group. However, FRB treatment groups showed the decreasing trend of plasma leptin level when compared to HF group (Fig. 3). On the other hand, hepatic IL-1β level of HF group was higher than that of NC group, whereas hepatic IL-1β level of HF+5% FRB group were significantly lower than that of HF group (Table 2). Furthermore, HF group showed the significantly higher NAFLD score when compared to NC group. In addition, NAFLD score was significantly reduced in HF+5% FRB group when compared to HF group (Fig. 4). Conclusion: It was found that rice bran had the higher anti-oxidative ability because of fermenting by Aspergillus kawachii. Furthermore, FRB-WE showed potential for preventing the liver damage induced by high fat diet which was represented as the lower NAFLD score. However, the pathological mechanism has to be explored in the further study. Keywords: water extract of fermented rice bran, non-alcoholic fatty liver disease, high fat diet, aged rats