The chem. components in Guizhi Fuling capsules by high performance liquid chromatog.-electrospray ionization-quadruple time of flight-mass spectrometry (HPLC-ESI-QTOF /MS) with ESI source were reported.These compounds were analyzed with an Agilent Eclipse XDB-C18 (4.6 mm × 250 mm, 5 μm) column by gradient elution using 0.1% formic acid and acetonitrile.The data were acquired in pos. ion and neg. ion modes.Eighteen compounds in Guizhi Fuling capsules were identified rapidly by direct comparison in both pos. and neg. modes of QTOF/MS, the elemental compositions anal., isotopic distribution, their fragmentation patterns and the previous referencesIt is a rapid and effective method which can be applied for the constituent identification of Guizhi Fuling capsules.