An ultra-performance LC in combination with MS/MS method was established to evaluate the quality of wu-yao (the dried root of Lindera aggregata (Sims) Kosterm. (Lauraceae)) through simultaneous quantitation of five sesquiterpene lactones, linderagalactone D (1), linderagalactone C (2), hydroylindestenolide (3), neolinderalactone (4) and linderane (5). All compounds were separated on a Waters Acquity ultra-performance LC HSS T3 column (2.1 mm x 100 mm, 1.8 microm particle size) with linear gradient elution of acetonitrile and 0.1% formic acid. An ESI interface in the positive mode was employed prior to MS detection. All the compounds showed good linearity (R(2) > or = 0.9992). The recoveries, measured at three concentration levels, varied from 97.3 to 103.4% with RSDs < 4.8%. The simple, rapid and reliable method was successfully applied to quantify the five components in 13 samples of wu-yao from different areas.