The brown alga Saccharina japonica is consumed as a foodstuff in many countries. Carbon tetrachloride ($CCl_4$) is a potent hepatotoxin that is used to assess hepatotoxicity in animal models. This study assessed the protective effect of S. japonica extract (SJE) on $CCl_4$-induced acute liver injury in rats. Experimental rats were divided into the following three groups: control, $CCl_4$, and $CCl_4$+SJE; the latter two groups were given 150 or 300 mg SJE/kg orally for 10 days. Three hours after the final treatment, all rats-except for those in the control group-were administered intraperitoneal injections of $CCl_4$. One day later, blood and liver samples were collected for evaluation biomarker of levels. Aspartate transaminase (APT; GPT) and alanine aminotransferase (ALT; GOT) levels were markedly lower in the $CCl_4$+SJE group than the $CCl_4$ group. The hepatic superoxide dismutase (SOD) activity of the $CCl_4$+SJE group was significantly lower than that of the $CCl_4$ group. In comparison, glutathione S-transferase (GSH) and catalase (CAT) levels were significantly higher in the $CCl_4$+SJE group. Western blotting revealed that SJE attenuated the $CCl_4$-induced EGFR and MAPK activity in the liver. Thus, we conclude that SJE protects against $CCl_4$-induced hepatotoxicity.