Two methods were developed for the quantitative analysis of phenolic acids in herb extracts. The methods were based on liquid chromatography-time-of-flight mass spectrometry (LC-TOFMS) and gas chromatography-mass spectrometry (GC-MS). The methods were compared in terms of their linearity, repeatability, selectivity, sensitivity and the speed of the analysis. The sensitivity was good for both methods, with limits of detection of <80 ng/ml for most of the compounds. The relative standard deviations (RSD) of the peak areas were on average 7.2% for the LC-TOFMS method and 1.4% for the GC-MS method. Both methods were found to be suitable for the determination of the target analytes, although GC-MS was better suited to the quantitative determination of compounds present at low concentrations.