A simple and sensitive high-performance liquid chromatographic method was developed for the determination and identification of magnolol to study its pharmacokinetics in rabbits after a 5 mg/kg i.v. bolus and 76 micrograms/kg/min i.v. infusion. Plasma concentration time profiles were suited to a two-compartment open model. The elimination half-lives of magnolol were 14.56 and 15.71 min, and the total body clearances were 75.86 and 72.72 ml/min/kg for i.v. bolus and i.v. infusion, respectively. There were no significant differences in elimination half-life and total body clearance between i.v. bolus and i.v. infusion, which suggests that magnolol pharmacokinetics are linear.