Objectives : This study was undertaken to verify the effects of Gyeongshingangjeehwan18 (GGEx18) on obesity using ob/ob male mice. Methods : Eight-week old mice (wild-type C57BL/6J and ob/ob) were used for all experiments. Wild-type C57BL/6J mice were used as lean control and obese ob/ob mice were randomly divided into 5 groups: obese control, GGEx15, GGEx16, GGEx17, and GGEx18. After mice were treated with several kinds of GGEx for 11 weeks, body weight gain, feeding efficiency ratio, plasma lipid and glucose metabolism. Results : 1. Compared with obese controls, GGEx-treated mice had lower body weight gain and feeding efficiency ratio, the magnitudes of which were prominent in GGEx16 and GGEx18. 2. Consistent with their effects on body weight gain, GGEx16 and GGEx18 not only decreased plasma triglycerides levels, but also increased HDL-cholesterol concentration. 3. CT analysis revealed that visceral fat areas were decreased in all treatment groups compared with obese control mice. The decrease in visceral fat area was prominent in GGEx16 and GGEx18, although they were not statistically significant. 4. The size of adipocytes were significantly decreased by GGEx18, whereas the adipocyte number per unit area was significantly increased, suggesting that GGEx18 decreased the number of large adipocytes. Hepatic lipid accumulation was decreased by GGEx16 and GGEx18, and the inhibitory effect was most effective in GGEx18. 5. Plasma GOT and GPT concentrations were significantly lower following GGEx16 and GGEx18 treatment compared with obese controls. Organ weights were not changed by GGEx treatment, indicating GGEx do not show any toxic effects. Conclusions : These results suggest that GGEx may regulate obesity. Of the 4 compositions, GGEx18 seems to be most effective in improving obesity and lipid disorders.