Objective: To observe effects of the prescription and drug for promoting blood circulation and eliminating phlegm in prevention of myocardial fibrosis in spontaneously hypertensive rate （SHR）. Methods: Changes of blood pressure （BP）

left ventricular mass/body weight （LVM/BW）

left ventricular wall thickness （LVWT） and content of myocardial collagen were investigated before and after treatment with the prescription and drug for promoting blood circulation and eliminating phlegm in SHR of 14 weeks in age. Results: SHR of 14 weeks in age has formed left ventricular thickness

and appeares gradually myocardial fibrosis with advance of disease course. After treatment with the prescription and drug for activating blood circulation and eliminating phlegm for 12 weeks

BP decreases

left ventricular thickness eliminates obviously

and the content of myocardial collagen does not increase in SHR. Conclusion: The prescription drug for promoting blood circulation can reverse the left ventricular thickness due to hypertension

and can prevent myocardial fibrosis.