Objectives: Samjung-hwan (SJH) is a Korean herbal formula that has been used for antilipidemic, antioxidant, and antidepressant effects. As a part of safety evaluation, single oral dose toxicity study of modified SJH in Sprague-Dawley (SD) rats was carried out.\nMethods: Modified SJH extract was administered orally in male and female SD rats at dose of 5,000 mg/kg. After single oral administration of modified SJH, we monitored the changes of mortalities, clinical signs, and body weight daily for 14 days. Gross necropsy findings were also evaluated at the end of the experiment.\nResults: Modified SJH extract did not induce any toxic signs in the changes of mortalities, clinical signs, and body weight. There were also observed no gross necropsy findings in rats.\nConclusions: As results, the approximate lethal dose of modified SJH extract in SD rats was considered to be over 5,000 mg/kg. This suggests that modified SJH is safe herbal formula for the treatment with.