Abstract: Simple,rapid and sensitive reversed phase high performance liquid chromatographic(RP-HPLC)method for the analysis of free ferulic acid in serum of rabbits with blood stasis has been developed.Coumarin was used as internal standard.0.2 ml of serum containing ferulic acid was deproteinized with acetonitrile which contained the internal standard (coumarin).The supernatant was evaporated to dryness.The residue was dissolved in 60 μl of acetonitrile.A Du Pont Zorbox C₁₈ column was used. A mixture of acetonitrile and 0.10 mol·L^-1 phosphoric acid(3:7,v/v,pH 2.5)was used as the mobile phase ,and UV detection was performed at 320 nm.The detection limit (signal-to-noise ratio=3)and the mean recovery from serum were 1 ng and 97.0±1.8%, respectively. The method was linear within the range of 20～800 ng· ml^-1(r=0.9986).The relative standard deviation were all less than 7%. The method was applied to pharmacokinetic studies in healthy rabbits and rabbits with blood stasis.Through this experiment we have found significant difference in the pharmacokinetic parameters between healthy rabbits and rabbits with blood stasis. The results obtained are coincident with syndrome and pharmacokinetics.