Abstract: The plasma concentration-time course of muscone in rats after a single iv administration fitted well to a two-compartment open model, and those in rabbits and dogs were all comformod to a three-compartment open model. Significant species differences were observed in the pharmacokinetic parameters among rats, rabbits and dogs, while no significant differences were found among the three dosages of 12,18 and 24 mg/kg after iv administration to rats. In rats, the T_1/2β was found to be 118. 1～131.2 min. In rabbits and dogs, the T_1/2β were 24.9 and 30. 0 min, respectively and the T_1/2γ were 331.9 and 366.4 min, respectively. In rats, rabbits and dogs, the V_ss were 23. 0, 51.7 and 7. 3 L/kg, respectively, and the V_C were 2.33, 2. 13 and 0. 38 L/kg, respectively.