Previous studies have shown that methanol extract and its butanol fraction of Carthamus tinctorius L. Semen have the hepatoprotective effect on the CCl4-induced hepatotoxicity. The hepatoprotective effect of subfractions has been evaluated by analyzing blood and hepatocyte biochemical analyses and biotransformation enzyme analyses. Treatment of BS-5, subfraction has significantly decreased the activities of alanine aminotransferase and aspartate aminotransferase. In addition, the levels of cholesterol and triglyceride in liver have been decreased as compared with that of CCl4 treated rats. The hepatoprotective effect of BS-5, subfraction on the CCl4-induced hepatotoxicity would be mediated of the attenuation of the level of cytochrome P450 and the enhancement of the activity of glutathion S-transferase.