Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SGT) has been developed as prescriptions for the Soyeumin constitution. The hepatoprotective effect of the water extract of Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SGT) was investigated against carbon tetrachloride (CCl4)-induced hepatic damage. A single intra-peritoneal injection of CCl4 produced liver damage in rats as manifested by the significant rise of aspartate aminotransferase(AST), alanine aminotransferase(ALT), and alkaline phosphatase(ALP) in serum as compared to those of untreated normal group. Pretreatments of rats with Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SGT) 500 mg/kg for 7 days) were significantly reduced AST, ALT, and ALP levels compared with CCl4-treated control group. Treatment of rats with CCl4 led to significantly increase in lipid peroxidation and significantly decrease in cytochrome P450 and P450 reductase. The oral administration of Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SGT) water extract significantly inhibited the accumulation of microsomal thiobarbituric acid reactive substance (TBARS) and increased the cytochrome P450 and P450 reductase activity. All these biochemical alterations resulting from CCl4 administration were inhibited by the pretreatment with Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SG1) extract. These results suggest that Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SGT) water extract can be useful as a hepatoprotective agent. And the effect of NO modulation by NO synthesis or precursors, and Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang (SGT) water extract was researched on chronic liver damage induced by CCl4 administration. It was observed that endogenous NO protected the liver from lipid peroxidation, fibrosis, and damage. Osuyubujaijung-tang(OBT) and Sipyimiguanjung-tang(SGT) water extract showed the hepatoprotective effect on the chronic liver cirrhosis model and relationship with NO modulation.