Juzentaihoto is a herbal medicine with reported anti-inflammatory effects, and it is predicted to improve inflammation and insulin sensitivity within obesity. In the present study, juzentaihoto hot water extract (JTT) was administered to obese type 2 diabetic model mice (KKAy) for 56 days. In addition, the effects of JTT on the adipose tissue, glucose metabolism, and blood lipids were evaluated for examining its impact on insulin sensitivity and obesity. As a result of JTT administration, KKAy mice exhibited suppressed adipocyte hypertrophy, decreased the mRNA levels of tumor necrosis factor α, and increased the mRNA levels of adiponectin in epididymal fat tissue. In addition, fasting blood glucose levels, blood triglyceride, and total cholesterol decreased. In summary, these data indicated that JTT administration suppressed the production of inflammatory cytokines and increased adiponectin levels in the adipose tissue. Therefore, with improved insulin sensitivity, blood glucose, and lipid decreased.