Aim of the study The clinical usefulness of medications generally depends on their efficacy and safety. Bangpungtongsung-san (BPTS), a traditional herbal medicine, is widely used to treat patients in Korea, Japan (Bofu-tsusho-san), and China (Fang feng tong sheng-san) as an antiobesity prescription. The objective of the present study was to evaluate the subchronic toxicity of a BPTS water extract in Crl:CD SD rats. Materials and methods BPTS was administered to rats orally once daily at doses of 0, 500, 1000, and 2000mg/kg/day for 13 weeks. Toxicological parameters included clinical signs, body weight, water and food consumption, ophthalmological signs, relative organ weight, hematological and serum biochemical parameters, and histopathological assessment. Results No treatment-related adverse effects were observed regarding the physiological parameters examined during the study or in the evaluation of blood, urea, and tissue samples taken from the animals at the end of the study. Conclusions In conclusion, the no-observed-adverse-effect-level for BPTS was determined to be a dietary dose of over 2000mg/kg for both sexes under the present experimental conditions.