Objectives & Methods : The objective of this study was to evaluate the single oral dose toxicity of Chongmyung-tang (CMT) in ICR mice. Korean traditional herbal prescription CMT has traditionally been used as a neuroprotective for treatment of learning disability and memory improvement. CMT, lyophilized aqueous extracts (yield=9.7%) were administered to female and male mice with oral dose of 2,000, 1,000 and 500 mg/kg (body weight) according to the recommendation of Korea Food and Drug Administration (KFDA) Guidelines. Animals were monitored for mortality, changes in body weight, clinical signs and gross observation during 14 days after administration upon necropsy; organ weight and histopathology of 14 principle organs were examined. Results : We could not find any CMT extracts treatment related mortalities, clinical signs, changes in body and organ weight, or gross and histopathological observations against 14 principle organs up to 2,000 mg/kg in both female and male mice, except for some accidental sporadic findings which did not show any obvious dose-relations and most of which also demonstrated in both the female and male vehicle control mice in this experiments. Conclusions : Based on the results of this experiment, the 50% lethal dose ($LD_{50}$) and approximate lethal dose (ALD) of CMT extracts after single oral treatment in female and male mice can be considered to be over 2,000 mg/kg, and is likely to be safe in humans.