Acute toxicity of a combined preparation of the standardized extracts Scutellaria baicalensis GEORGI and Salvia miltiorrhiza BUNGE in a ratio of 3:1 was examined in male and female ICR mice. Mice were treated with the test substance intragastrically at a dose of 0 mg/kg, 5 mg/kg, 50 mg/kg, 500 mg/kg or 2,000 mg/kg and observed for two weeks. No death or abnormal clinical sign was shown during the observation period. Also there were no difference in net body weight gain, organ weight, and gross pathological findings at the terminal sacrifice. The results suggested that acute oral toxicity of a combined preparation of the standardized extracts is very low at the conditions employed in this study.