The anti-obesity effects of MPP, a formulation composed of polycan (β-glucan produced by Aureobasidium pullulans) and platycodin (purified from Platycodi radix) at an optimal ratio, were observed in obese db/db mice. The animals were treated by MPP at 50, 100, and 200 mg/kg, polycan or platycodin at 100 mg/kg, or metformin at 250 mg/kg via daily oral administration for 28 days. During the experimental period, the changes in body weight, epididymal fat weight, serum leptin and adiponectin levels, adipose adiponectin content, and liver triglyceride content were monitored. Prior to initial administration of the test compounds, control db/db mice showed noticeable obesity with severe hyperglycemia compared to db/m mice. The epididymal fat weight, serum leptin level, and liver triglyceride contents in the db/db control were significantly higher than those in the db/m mice, whereas serum and adipose adiponectin levels were significantly lower. At all dosages, MPP attenuated these levels of these obesity-related indicators in a dose-dependent manner. In addition, MPP showed stronger anti-obesity effects compared to those of equal-dose polycan or platycodin administered individually by limiting intestinal fat absorption as an anti-obesity mechanism. Taken together, MPP is expected to be beneficial to patients with obesity or related metabolic diseases such as diabetes.