Objective: To investigate the effect of different extracts of Cydonia oblonga Mill. (COM) fruits and leaves on blood pressure and hemorheology in renal hypertensive rats(RHR). Method: Two-kidney

one-clip (2K1C) rat model was established and divided randomly into eleven groups:sham group

model group

low and high dosage of aqueous extracts of COM fruits groups

low and high dosage of ethanol extracts of COM fruits groups

low and high dosage of aqueous extracts of COM leaves groups low and high dosage of ethanol extracts of COM leaves groups(80

160 mg·kg-1) and captopril group (25 mg·kg-1)(n=10

each). The drugs were administered for eight weeks;systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured before administration and every 2 weeks

the changes of hemorheology perameter were examined after the last administration. Result: After treatment for eight weeks

in all groups of COM fruits and leaves extracts the SBP and DBP of RHR were lowered in different degrees(P<0.05)

the whole blood viscosity

plasma viscosity

hematocrit

erythrocyte aggregation index and erythrocyte rigidity index were declined(P<0.05)

the erythrocyte deformability index was elevated(P<0.05). The effects of ethanol extracts groups were better. Conclusion: COM extracts have antihypertensive activity and certain influence on hemorheology perameter

and the active ingredients are higher in ethanol extracts.