Methyl salicylate is a compound currently used in the creation of many flavors. It can be obtained by synthesis or from two natural sources: essential oil of wintergreen and essential oil of sweet birch bark. Deuterium site-specific natural isotope abundance (Ai) determination by NMR spectroscopy with the method of reference ERETIC (2H-ERETIC-NMR) has been applied to this compound. Ai measurements have been performed on 19 samples of methyl salicylate from different origins, natural/synthetic and commercial/extracted. This study demonstrates that appropriate treatment performed on the data allows discrimination between synthetic and natural samples. Moreover, the representation of intramolecular ratios R6/5 as a function of R3/2 distinguishes between synthetics, wintergreen oils, and sweet birch bark oils.