Objective : Bangpungtongseongsan(BTS) has been used in oriental medicine for many centuries as a prescription for a heat syndrome of apoplexy. The effects of BTS on the vascular system are not well known. This study is designed to identify the effects of BTS on the regional cerebral blood flow(rCBF), arterial blood pressure and action mechanism in mice. Methods : We measured the change of rCBF and BP by BTS. Secondly, we investigated changes of rCBF and BP for 30 minutes interval after venous inject 0.01, 0.1, 1.0, 10.0mg/kg each density BTS infusion into mice, which were premanaged with methylene blue(10mg/kg, i.v), indomethacin(3mg/kg, i.v.), propranolo(3mg/kg, i.v.) for 30minutes. Results : rCBF increased significantly by BTS in a dose-dependent and BP was not affected by BTS in mice. Pretreatment with methylene blue significantly inhibited rCBF increased by BTS and aceelrated BP not affected by BTS. Pretreatment with indomethacin significantly inhibited rCBF increased by BTS and inhibited BP not affected by BTS. Conclusion : These results show that BTS causes the increasement of rCBF and non-change of BP. The action mechanism is related to prostaglandid activated by cyclooxygenase.