Objective: To explore the effects of dispensing ratio of Chinese herbs on the pharmacokinetics characteristics of effective component.Methods: Ferulic Acid(FA)in serum was determined by RP-HPLC with UV-detector.The concentration-time data were fitted using 3P87 Pharmacokinetic Program

and the pharmacokinetic parameters were compared byt-test.Results: By adminstrating Xiongshao preparation of 5 g·kg-1intragastically

the concentration-time curves of FA in canine groups of Chuanxiong: Chishao=1∶2 and Chuanxiong:Chishao=2∶1 both fitted to open one-compartment model.Parameters of Chuanxiong:Chishao=1∶2 and Chuanxiong:Chishao=2∶1 group were:Ka=0.111±0.035(min-1) and 0.075±0.020(min-1)

Ke=0.013±0.004(min-1) and 0.016±0.002(min-1)

t1/2Ka=6.701±1.926(min) and 9.735±2.377(min)

t1/2Ke= 61.306±23.531(min) and 44.254±5.518(min)

tpeak=24.915±5.307(min) and 29.339±4.101(min)

cmax=557.797±172.903(μg·L-1) and 1509.518±275.813(μg·L-1)accordingly.The differences of pharmacokinetic parametersKaandt1/2Kabetween the two groups were statistically significant(P<0.05 ).Conclusion:The difference in dispensing ratio of herbs in Chinese formulae may result in changes of the pharmacokinetic characteristics of the components.