In this study, we investigated the acute toxicity and safety about fermented Bangpungtongsung-san(Fangfengtongsheng-san) extract. Methods To evaluate the acute toxity and safety, fermented Bangpungtongsung-san (Fangfengtongsheng-san) at the respective doses of 0(control group), 1250, 2500 and 5000 ㎎/㎏ were orally treated to 20 male and 20 female mice. After single administration, we observed survival rates, general toxicity, changes of body weight and autopsy. Results Compared with the control group, we could not find any toxic alteration in all treated groups (1250, 2500 and 5000 ㎎/㎏). Conclusions LD50 of fermented Bangpungtongsung-san(Fangfengtongsheng-san) extract might be over 5000 ㎎/㎏ and it is very safe to ICR mice.