Ceramide plays a crucial role in promoting liver fibrosis by inducing apoptosis and inflammation in hepatocytes. Oxidative stress accelerates fibrosis by elevating levels of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), an indicator for the damage of DNA. We aimed to evaluate the efficacy of eicosapentaenoic acid encapsulated in cellulose nanocrystals (EPA-CNC) in inhibiting ceramide accumulation and reducing urinary 8-OHdG levels, thus providing protective effects against the progression of liver fibrosis. In this study, twenty-four adult male Wistar albino rats were allocated into a negative control group, a group with liver fibrosis induced by diethylnitrosamine (DEN), and a group with DEN-induced liver fibrosis treated simultaneously with EPA-CNC. Key parameters assessed included liver paraoxonase-1 (PON-1), plasma interleukin-6 (IL-6), plasma ceramide, liver hydroxyproline (Hyp) content, and urinary 8-OHdG. DEN-induced liver fibrosis led to a significant increase in inflammatory markers, including ceramide, IL-6, and notably urinary 8-OHdG. This was accompanied by a decrease in PON-1 activity and increased collagen deposition in liver tissues (Hyp content). Histopathological analysis revealed a substantial loss of liver architecture, with inflammation and fibrosis surrounding necrotic areas. In contrast, treatment with encapsulated EPA-CNC resulted in a significant decrease in plasma ceramide, IL-6, liver Hyp content, and urinary 8-OHdG levels, along with an improvement in liver PON-1 activity. Histopathological findings showed nearly normal liver architecture. In conclusion, increased levels of ceramide and urinary 8-OHdG could serve as indicators of ongoing hepatocellular damage due to their positive correlations with fibrotic markers. Encapsulated EPA-CNC may offer a promising approach for halting oxidative stress and inflammation in liver fibrosis.