An aqueous extract of oriental herbal composition named Onchengyeum and curcumin, an antioxidant isolated from turmeric (Curcuma Zonga L.) reduced hepatotoxicity induced by carbon tetrachloride ($CCI_4$). Improved liver function was observed by measuring the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), creatinine (CRE), total cholesterol (T-CHO), triglyceride (TG), low density lipoprotein cholesterol (LDL-CHO), high density lipoprotein cholesterol (HDL-CHO), total protein (TP), albumin (ALB) and total bilirubin (BIL) in serum. Hepatic parameters monitored were levels of cholesterol (CHO), triglyceride (TG), and malondialdehyde (MDA) and activities of cytochrome P450 (CYP), NADPH-CYP reductase, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione S-transferase (GST), glutathione reductase (GR), and glutathione peroxidase (GPx). The histopathological examination showed that the treatment of Onchengyeum and curcumin relieved the ballooning degeneration of hepatocytes which had been generated by $CCI_4$. The results suggested that hepatoprotective effects of Onchengyeum and curcumin possibly are due to their promising antioxidative activity.