Anthocyanins can be considered spy-substances, useful in obtaining information regarding the shelf-life of food supplements containing cranberry juice or cranberry-derived extracts. The level of total anthocyanins, as evaluated by high-performance liquid chromatography-diode-array detector and analytically expressed as cyanidin aglycone, represents a 'quality index' useful for routine estimation of shelf-life. The objective of this work was to study the stability of anthocyanins in a commercial cranberry (Vaccinium macrocarpon) dried extract compared with the stability of the same extract contained in a food supplement enriched with alpha-tocopheryl succinate and ascorbic acid. The values obtained after exposure of the samples to natural light and to alternating hot and cold temperatures show considerable sensitivity of the commercial cranberry dried extract to the agents used for the same evaluation (time, temperature and light) and emphasize a positive effect of the enrichment of the derived preparation with alpha-tocopheryl succinate and ascorbic acid.