Purpose: This study is to examine anti-obesity effect and cytotoxicity of the long-term oral administration of Sinomenium acutum (Bang-gi, SA) Methods: Using diet-induced obesity C57BL/6 mouse model, anti-obesity effect and DNA chip expression and cytotoxicity of the long-term oral administration of this herbal extract were investigated. Results: The herbal extract treated groups were arrested in weight increment only when they were lodged together. Such effects were abolished when they kept individually. SA fed mice behaved very rudely and violently. On the basis of histological studies of liver tissues and also in vitro cytotoxicity tests of the liver and kidney cell lines, no significant toxicity was found by 14 weeks of SA treatments. However, we found significant changes in gene expression profile in SA treated group by micro-array analysis. In case of SA group, up-regulated genes were 1,213 and down-regulated ones were 2,558. Some of lipid metabolism related genes also significantly changed in both treatment groups. Conclusion: SA had effects of increasing the basal metabolic rate by stimulating the sympathetic nervous systems.