Technical Abstract: Scutellaria lateriflora, commonly known as skullcap, is used as an ingredient in numerous herbal products. However, it has been occasionally adulterated/contaminated with Teucrium canadense and Teucrium chamaedrys, commonly known as germander, which contain potentially hepatotoxic diterpenes. Due to the similarities between the two species botanically, rapid analytical methodologies to distinguish authentic S. lateriflora from Teucrium species are needed to ensure public safety. In this study, a direct injection electron-spray ionization-mass spectrometry (ESI-MS) method was used to generate MS spectrum fingerprints of extracts from 23 skullcap and germander samples in 90 seconds for each sample. MS spectrum fingerprints of the samples were analyzed according to the m/z of the key compounds. Principal component analysis (PCA) was also used to process the MS fingerprints. The newly developed method offers a fast and easy way to differentiate between the skullcap and germander in samples.