Xiao-xu-ming decoction (XXMD) is a traditional Chinese medicine that has been widely used to treat theoplegia and its sequelae. This paper reports the development of three separate assays based on reversed phase high-performance liquid chromatography–mass spectrometry (HPLC–MS) and HPLC–MS/MS for the determination of seven active constituents of XXMD viz oroxylin A-7-O-glucuronide, wogonoside, liquiritigenin, cimifugin, 5-O-methylvisammiol, glycyrrhizic acid and glycyrrhetinic acid in rat plasma. All calibration curves were linear (r >0.99) with lower limits of quantitation (LLOQs)<12.4 ng/mL. Intra- and inter-day precisions (as relative standard deviation) were all <10.7% with recoveries in the range of 88.7–113%. In addition, the seven analytes were shown to be stable in rat plasma samples under relevant storage conditions. The validated methods were successfully applied to a pharmacokinetic study in rat after oral administration of XXMD.