Effects of Ryangkeogsanwhatang on the obesity of white mouse induced by gold thioglucose. It is researched to elucidate the effect of Ryangkeogsanwhatang on the obesity of white mouse induced by gold thioglucose and the differentiation and growth of preadipocyte, 3T3-L1. The result were as follows. 1. Ryangkeogsanwhatang extract improved the blood level of transaminase changed by the obesity of white mouse induced by gold thioglucose. 2. Ryangkeogsanwhatang extract inhibited the increase of liver fat and body fat induced by the obesity of white mouse induced by gold thioglucose. 3. Ryangkeogsanwhatang extract inhibited the increase of body weight induced by the obesity of white mouse induced by gold thioglucose. 4. Ryangkeogsanwhatang extract inhibited the growth of undifferentiate preadipocyte 3T3-L1. 5. Ryangkeogsanwhatang extract showed inhibitory on the differentiation of preadipocyte 3T3-L1. The above results suggest that the Ryangkeogsanwhatang extract may be used on the obesity induced by the overgrowth and differentiation of adipocyte, and the accumulation of fat in liver and body.