Objective: To investigate pharmacokinetics and tissue distribution of 3-keto- dehydrosulfurenic (3-keto-DSA) from Fomes officinalis in rats. Method: After oral administration of 12.5 mg·kg-1 and intravenous administration of 5 mg·kg-1to rats

blood concentration at different time point of 3-keto-DSA were determined by HPLC

parameters and bioavailability were calculated by 3P97 software.Tissue distribution of 3-keto-DSA in rats was studied after oral administration with dose of 25 mg·kg-1. Result: Two compartment model was fitted to 3-keto-DSA

its main pharmacokinetic parameters of 3-keto-DSA were as follows:t1/2ka of 0.381 h

t1/2α of 0.415 h

t1/2β of 3.852 h

tmax of 0.690 h

Cmax of 0.059 mg·L-1

F of 32.84%.The 3-keto-DSA was rapidly

extensively distributed to various rat tissues after oral administration of 25 mg·kg-1

time to reach maximum tissues concentration was about 30 min and it almost eliminated after 3 h.The concentration of 3-keto-DSA in each tissues was in the order of liver > spleen > heart > kidney. Conclusion: After oral administration

3-keto-DSA can be absorbed rapidly and distributed widely in blood and tissues

but its bioavailability is low.