Abstract: Baicalein nanosuspension was prepared by antisolvent recrystalization method combined with subsequent homogenization.The oral bioavailability of baicalein nanosuspension in rats was also studied.The concentration of baicalin in rat plasma was determined by HPLC method.The pharmacokinetic parameters were calculated by DAS 2.0 software.It was found that the plasma drug concentration-time curves of baicalein all showed two peaks after oral administration.The c_max,t_maxand AUC0-24 h of the raw baicalein and baicalein nanosuspension was 7.18 and 11.12 μg/mL,1.67 and 0.92 h,71.40 and 118.63 μg·h/mL,respectively.Compared with baicalein bulk,the relative bioavailability of baicalein nanosuspension was 166.1%.Nanosuspension could significantly enhance the oral bioavailability of baicalein in rats.