The object of this study was to evaluate the single dose toxicity of Taeumjowui-tang(TUJWT), a polyherbal formula have been traditionally used as prevention or treatment agent for obesity, in male and female mice. Aqueous extracts of TUJWT (Yield = 10.5%) was administered to female and male ICR mice as an oral dose of 2000, 1000 and 500 mg/kg (body wt.) according to the recommendation of KFDA Guidelines. Animals were monitored for the mortality and changes in body weight, clinical signs and gross observation during 14 days after dosing, upon necropsy, organ weight and histopathology of 12 principle organs were examined. As results, we could not find any mortality, clinical signs, and changes in the body and organ weight except for diarrhea restricted in TUJWT 2000 mg/kg treated one male mouse at 1 day after administration, and increases of popliteal lymph node weights in all TUJWT administered groups. In addition, no TUJWT-treatment related abnormal gross findings and changes in histopathology of principle organs were detected except for increases of the frequency of hypertrophy and hyperplasia of lymphoid cells in the popliteal lymph nodes in all TUJWT treatment groups with some sporadic accidental findings. These increases of popliteal lymph node weights with hypertrophy and hyperplasia of lymphoid cells were considered that related to the immune modulate effect of TUJWT not toxicological signs. The results obtained in this study suggest that the TUJWT does not cause any toxicological signs. The 50% lethal dose and approximate lethal dose of TUJWT aqueous extracts in both female and male mice were considered as over 2000 mg/kg.