Misaengtang (MST), a formula of Korean herbal medicines, has been used as a weight-controlling recipe. We have investigated two experiment of body weight regulation by MST In rats. i) The anti-obesity effect of MTS on a high fat diet-induced obesity, male Sprague-Dawley rats were fed with a high-fat diet containing 30% in the absence or presence of MST (0.3, 1 or 3%) or a reference orlistat (0.05%) for 6 weeks. ii) weight-decrease effect of MST on normal diet, same animal were fed with a normal diet in the absence or presence of MST (3%) for 6 weeks. And the body weights, daily feed and water consumptions, organ weights, fat weights serum biochemistry were measured. In both experiments, MST and orlistat did not affect the body weight gain. But orlistat significantly increased the feed and water consumptions, leading to low-feed efficiency, and orlistat markedly reduced abdominal, paratesticular and perirenal fat weights, although increased the kidney weights. In MST, low dose (0.3%) of MST decreased the perirenal fat and increased the kidney weights in rats fed HFD, and MST 3% decreased the abdominal fat weights in rats fed normal diet. In addition, Orlistat caused changes in parameters of hepatotoxicity (AST and glucose), nephrotoxicity (BUN and B/C ratio) and lipid metabolism (HDL and triglycerides). In comparison, MST decreased AST, ALP and ALT, the hepatotoxicity markers, and somewhat improved the hepatic fatty degeneration. Taken together, it is suggested that MST does not exert anti-obesity activity as well as remarkably direct effects, but MST may be potentially benefit for dietary cure and exercise-cure of obesity.