The purpose of the present invention is to provide a method of masking the characteristic off-flavor derived from ornithine and salts thereof, said off-flavor being problematic when adding ornithine or a salt thereof as a health-promoting functional ingredient to a food or beverage composition, and to provide a food or beverage composition which achieves excellent aroma by using said method to mask the characteristic off-flavor perceived when orally ingesting ornithine or a salt thereof. The present invention is a method of masking the off-flavor derived from ornithine or salts thereof, and is characterized by admixing one or more vanillins, comprising vanillin, ethyl vanillin and methyl vanillin, with a ratio of 0.5-25 parts by weight per 100 parts by weight of ornithine or a salt thereof. Further, the present invention provides a food or drink composition in which the off-flavor derived from ornithine or a salt thereof is masked in that this method for masking the off-flavor derived from the ornithine or salt thereof is applied in a food or beverage composition containing ornithine or a salt thereof as a health-promoting functional ingredient.
