The present invention has objects to provide a method for inhibiting the formation of volatile aldehydes and/or the decomposition of fatty acids and use thereof. These objects are attained by establishing a method which comprises incorporating an alpha -oligoglucosyl alpha , alpha -trehalose(s) to a target product to inhibit the formation of volatile aldehydes per se and/or the decomposition of fatty acids per se in fatty acid-containing products； an inhibitory agent for inhibiting the formation of volatile aldehydes and/or the decomposition of fatty acids, which contains an alpha -oligoglucosyl alpha , alpha -trehalose(s) as an effective ingredient； and use thereof to thereby obtain various compositions such as food products, cosmetics, pharmaceuticals, and their materials and intermediates each having a high quality and stability.
