This study was designed to investigate the effects of a new herbal medicine named CWS-A on the changes in regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in normal rats, and further to determine the mechanism of action. Also, this study was designed to investigate the effects of CWS-A on the changes in rCBF in cerebral ischemic rats and the safety examination of CWS-A in rats regared to body weight change, renal and liver function test, CBC, $LD_{50}$ and histological observation in rats. The rCBF was significantly and stably increased and MABP was significantly decreased by CWS-A during the period of cerebral reperfusion in normal rats. However, there were no here were no significant changes of rCBF in ischemic rats. In additional, there were no significant changes on the safety examination. In conclusion, these results suggest that medication of CWS-A is effective for the improve the cerebral blood flow and CWS-A can be prescribed as vertigo(眩暈) symptoms treatment.