Heat-processed Gynostemma pentaphyllum and its methanol extract showed more potent cytotoxic activity against human non-small cell lung carcinoma A549 cells than that of the crude plant in the same way just like ginseng.This study was carried out to investigate the contents of the major constituents in heat-processed G.pentaphyllum using ultra high performance liquid chromatography with tandem mass spectrometry.Four dammarane-type saponins, gypenoside L, gypenoside LI, damulin B and damulin A, were successfully separated in less than 10 min.The mobile phase was composed of water and acetonitrile with gradient elution system at a flow rate of 0.25 mL/min.Their calibration curves showed good linear regression (r > 0.999) within the test ranges.The method was validated for specificity, accuracy, precision, and limits of detection.The contents of gypenoside L, gypenoside LI, damulin B and damulin A from the leaves of G.pentaphyllum were significantly increased after heat processing.