Acute toxicity of BDR-29, a combined preparation of Cassia Semen, Prunellae Spica, Tribuli Fructus, and Uncariae Rhamulus et Uncus was examined using male and female Sprague-Dawley rats. Rats were treated with the BDR-29 intra-gastrically at 0 mg/kg, 5 mg/kg, 50 mg/kg, 500 mg/kg or 2,000 mg/kg and observed for two weeks. At the doses used no mortality or abnormal clinical signs in animals were shown during at the observation period. Also there was no difference in net body weight gain, gross pathological findings, and urine analysis at the terminal sacrifice among the groups rats treated with different doses of the test substance. The results suggested that acute oral toxicity of BDR-29 in rats is very low at the conditions employed in this study.