Objectives : We experimented with Daesiho-tang in order to investigate the effects on the weight of obesity. Methods : We fed a control group of rats a high fat diet and administerd normal saline for 6 weeks. And we fed an experimental group of rats a high fat diet and administered an extracted of Daesiho-tang for 6 weeks. Results : Daesiho-tang suppressed the increasing amount of body weight in comparison with control group. The serum total cholesterol level, free fatty acid level in Daesiho-tang group showed a significant decrease in comparison with control group. The serum triglyceride, total lipid level in Daesiho-tang group showed a decrease in comparison with control group, but this result showed no efficacy. Conclusions : We concluded that the clinical application of Daesiho-tang can help the treatment of obesity.