Objective: To compare the pharmacologic effects of Sini decoction with dosages of different convertsion criteria. Method: Forty male Wistar rats were randomly divided into four groups: blood-letting hypotension group (control group)

Sini decoction low

middle and high dosage groups(SND-L group

SND-M group and SND-H group). The model of hypotension was replicated by blood-letting. The curves of blood pressure (BP)

heart rate (HR)

respiratory (R) were recorded during experiment by physiological polygram. At the end of the experiment the changes of curves were analyzed. Result: To be compared with control group

mean systolic pressure(MSP)

HR

respiratory frequency(RF) were increased significantly in SND-L group. MSP and HR were increased significantly in SND-M group. HR was increased significantly in SND-H group. There was no significant difference among groups in mean diastolic pressure (MDP) and mean arterial pressure (MAP). Conclusion: Sini decoction with proper dosage could elevate BP

strengthen heart and promote respiratory function in blood-letting hypotension rats

protect and maintain the function of vital organs. However

no enhanced effects obviously appeaved as the dosage increased. side-effect were noted when high dosage (especially Aconiti Lateralis Radix Preparata) was used. These results suggest that we should pay more attention to the possible risk when increasing the dosage of Sini decoction in clinical practice.