Objectives : This experimental study was designed to investigate the effects of Galgunseunggi-tang on the weight of obese rats Induced by high fat diet. Methods : A series of have been conducted in order to measure the effects of the above materials weight. serum and fat cells. The have been performed on; (1) the Increasing amount of body weight; (2) the quantity of total cholesterol, tryglyceride, total lipid, free fatty acid, phospholipid, HDL -cholesterol and LDL -cholesterol in serum; (3) the average size of epididymal fat cells and the area rate of fat drops in hepatic lobule. Results : The results were summarized as follows: 1. It was proved that Galgunseunggi-tang suppressed the increasing amount of body weight. GS II group (supplied 60mg per 100g) showed a significant value. 2. It was proved that Galgunseunggi-tang improved the total cholesterol, HDL -cholesterol In serum. but did not show a significance. 3. It was proved that Galgunseunggi-tang decreased the quantify of free fatty acid, phospholipid, LDL -cholesterol in serum. GS I group (supplied 30mg per 100g) showed a significant value. 4. It was proved that Galgunseunggi-tang decreased the quantity of triglyceride, total lipid in serum, and GS II group showed a significant value. 5. Galgunseunggi-tang decreased the average size of epididymal fat cells and the area rate of fat drops In hepatic lobule, and GS I group showed a significant value. Conclusions : Based on the above result, it is assumed that the clinical application of Galgunseunggi-tang can help the treatment of obesity.