Objective: To study pharmacodynamic of Huahong tablets and its main component——quercetin's pharmacokinetics in vivo in order to investigate the preliminary correlation of pharmacokinetics and pharmacodynamics(PK-PD). Method: Analgesic effect of Huahong tablets was studied by the writhing testinduced by acetic acid and hot plate method in mice

the serum concentration of quercetin as Huahong tablets active ingredient was determined by HPLC assay

and correlation analysis on effect-time curve and effect-blood concentration curve;PK-PD model were fitted on drug effect-plasma concentrations with WinNonlin software. Result: Huahong tablets have a significant analgesic effect between 1 and 3 hours

compared with the peak time of the concentration-time curve of quercetin

analgesic effect was lag certainly. Conclusion: Huahong tablets have a significant analgesic effect

pharmacodynamics of Huahong tablets and its main component-quercetin's pharmacokinetics are relevant. The relationship between increment percentage of analgesic threshold and plasma concentrations can meet the simple maximum effect PK-PD model;the relationship between inhibition rate of analgesia and plasma concentrations meet the simple maximum effect PK-PD model.