Objectives : This study aimed to evaluate the single oral dose toxicity of Jaeumganghwa-tang (Ziyinjianghuo-tang) and Jaeumganghwa-tang (Ziyinjianghuo-tang) fermented with Lactobacillus acidophyllus in male and female ICR mice. Methods : In this single oral toxicity study, non-fermented and fermented Jaeumganghwa-tang (Ziyinjianghuo-tang) were administered to male and female ICR mice as an oral dose of 500, 1000 and 2000 mg/kg. After single administration, body weight changes, general behavior, adverse effects and mortality were determined for 14 days. Serum chemistry, organ weights and necropsy findings were evaluated at the end of the experiment. Results : There were no mortality or signs of toxicity for 14 days. There were also no significant differences in body weights, organ weights, or serum chemistry values between treatment and control groups. Conclusions : These results indicate that the 50% lethal dose of Jaeumganghwa-tang (Ziyinjianghuo-tang) fermented with Lactobacillus acipophullus may be over 2000 mg/kg. This finding can be expected to provide scientific evidence for the safety of Jaeumganghwa-tang (Ziyinjianghuo-tang) fermented with Lactobacillus acidophyllus.