Objectives : The object of this study was to obtain acute information (single oral dose toxicity) of Scutellariae Radix Aqueous Extracts (SR; yield = 27.20%) which traditionally have been used in Korean medicine for treating various diseases including inflammatory diseases. Methods : In order to observe the 50% lethal dose ($LD_{50}$), approximate lethal dosage (ALD) and target organs, SR Aqueous Extracts were once orally administered to female and male ICR mice at dose levels of 2,000, 1,000, 500 and 0 (control) mg/kg (body weight.) according to the recommendation of KFDA Guidelines. The mortality and changes on body weight, clinical signs and gross observation were monitored during 14 days after single oral treatment of SR according to KFDA Guidelines with organ weights and histopathological observations of 14 types of principle organs. Results : After single oral treatment of SR, we could not find any mortality and toxicological evidences up to 2,000 mg/kg treated group, the limited dosages in rodents, on the body and organ weights, clinical signs, gross and histopathological observations, except for some accidental findings. Conclusions : The results obtained in this study suggest that the $LD_{50}$ and ALD of SR in both female and male mice after single oral treatment be considered as over 2,000 mg/kg because no mortalities were detected up to 2,000 mg/kg that was the highest dose recommended by KFDA and OECD, and can be safely used in clinics.