The objective of this study is to measure the changes of regional cerebral blood flow(rCBF) and blood pressure(BP) in rats, following the intravenous injection of drug. The measurement was continually monitored by laser-doppler flowmeter (Transonic Instrument, USA) and pressure tranducer(Grass, USA) in anesthetized adult Sprague-Dawley rats for about 2 to 2 and a half hours through the data acquisition system composed of MacLab and Macintosh computer. The result of this experiment was as following 1. Poria increased the changes of rCBF in rats, significantly. 2. The rCBF of Poria was significantly decreased by pretreated propranolol, but not by pretreated L-NNA. 3. Radix Cynanchi Wilfordii decreased the changes of rCBF in rats, significantly. 4. The rCBF of Radix Cynanchi Wilfordii was not changed by pretreated propranolol and L-NNA. 5. Poria and Radix Cynanchi Wilfordii increased the changes of rCBF in rats, significantly. 6. The rCBF of Poria and Radix Cynanchi Wilfordii was significantly decreased by pretreated propranolol, but not by pretreated L-NNA. 7. Poria decreased the changes of BP in rats, significantly. 8. The BP of Poria was significantly increased by pretreated propranolol and L-NNA. 9. Radix Cynanchi Wilfordii did not change the BP in rats. 10. The BP of Poria and Radix Cynanchi Wilfordii did not change by pretreated propranolol but was increased by pretreated L-NNA. According to the result above, Poria and Radix Cynanchi Wilfordii have a different effect on each other, extract together. It is considered that the effect of Poria and Radix Cynanchi Wilfordii increased that of each drugs, the increasing rCBF of Poria and Radix Cynanchi Wilfordii is mediated by adrenergic β-receptor.