Gamiwalbitang (GWB) is a newly developed dietary supplement that is composed of four herbs. The purpose of GWB development is to help control weight. The aim of this study was to investigate whether GWB combined with a 40% high-fat (HF) diet can influence body weight and fat accumulation. An experiment was conducted with 40 C57BL/6J mice with an initial body weight of approximately 18g. Body weight was recorded weekly, and plasma levels of triglyceride, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and leptin were analyzed at the end of the study. Weight increases in the 10% GWB group were 38.5% less than in the HF diet group (P < 0.05). Plasma triglyceride and LDL cholesterol levels decreased by 21.2% and 51.0%, respectively, in the 5% GWB group, and 44.1% and 51.5%, respectively, in the 10% GWB group compared to the HF diet group. The HDL cholesterol level was increased by 184.0% in the 5% GWB group and 188.2% in the 10% GWB group. The serum leptin level was significantly decreased by the GWB diet, and in the GWB diet group; gene expression of leptin in adipose tissue was also decreased compared with HF diet group. These findings indicate that GWB may be beneficial in the regulation of high-fat diet-induced blood circulatory disorders.