Objectives : This study was conducted to evaluate the acute toxicity and safety of Gumiganghwal-tang (Jiuweiqianghou-tang) in Sprague-Dawley rats though the current regulatory guideline. Methods : The preliminary study showed that the single oral administration of Gumiganghwal-tang(Jiuweiqianghou-tang) did not induce any toxic effect at a dose level of 2000 mg/kg. Based on the results, 2000 mg/kg was selected as the limited dose. In this study, 10 rats of each sex were randomly assigned to two groups of 5 rats each and were administrated singly by gavage at dose levels of 0 and 2000 mg/kg. Mortalities, clinical signs, and body weight changes were monitored for the 15-day period following administration. At the end of observation period, all animals were sacrificed and complete gross postmortem examinations were performed. Results : Throughout the study period, no treatment-related deaths were observed. There were no adverse effects on clinical signs, body weight, and gross findings at all treatment groups. Conclusions : These results showed that the single oral adminstration of Gumiganghwal-tang(Jiuweiqianghou-tang) did not cause any toxic effect at the dose levels of 2000 mg/kg in rats. In conclusion, the $LD_{50}$ of Gumiganghwal-tang (Jiuweiqianghou-tang) was considered to be over 2000 mg/kg body for both sexes.