Abstract: OBJECTIVE To determine the plasma concentration of gastrodin and evaluate the pharmacokinetics of the gastrodin capsule. METHODS We developed an LC-MS/MS assay method using aciclovir as the internal standard to determine the plasma concentration of gastrodin. An Atlantics T3 column (100 mm×3.0 mm, 3 μm) and the mobile phase of CH3CN-water (10∶90) were used for LC-ESI (-) and MRM for MS. RESULTS A simple and specific method has been developed to determinate the plasma concentrations of gastrodin by LC-MS/MS. Each plasma sample was preprocessed by adding methanol, and analysised within 2 minutes. No significant interfering peaks were observed. The lower limit of quantitation was 3.00 ng∙mL^-1. An oral dose of gastrodin capsules was given to 18 healthy male volunteers. The pharmacokinetic parameters of the test capsule were as follows: the T_max were (0.8±0.3)h, the t_1/2 were (2.15±0.38)h, the C_max were (378±84) ng∙mL^-1, the AUC_0-12 were (878±175) ng∙h∙mL^-1，the AUC_0-∞ were(897±175)ng∙h∙mL^-1, respectively. CONCLUSION The method is simple in pretreatment and is rapid, sensitive and accurate in analysis. This method was successfully applied to study the pharmacokinetics of gastrodin in healthy Chinese volunteers.