Abstract: The pharmacokinetics of artesunate (AS)was studied in 3 cows, single dose of AS (5mg/kg) were administered intravenously and the drug concentrations were determined by means of a TLC method developed in our laberatory, The plasma drug concentration-time course of AS, after the treatment with a pharmacokinetic microcomputer program MCPKP edited by Wen-Jiang Xia, was found to be best fitted to a two compartment open model and its pharmacokinetic parameters were as follows, T_1/2α=2.43 min, T_1/2β=31.45 min, V₁=0.124 L/kg, V_B=0.937L/kg, Cl_B=0.0215 L/kg. min, AUC=236mg/L·min. Dihydroartemisinine (DHA), the main active metabolite of AS in the bodies, was detected simultaneously. Peak plasma concentration of 3.5μg/ml of DHA was reached at about 3 minutes after dosing and the AUC was 82 mg/L·min.