In this work the storage stability of a Maytenus ilicifolia phytopharmaceutical preparation produced by spouted bed drying was investigated. Powder samples of M. ilicifolia extracts were submitted to stress storage conditions at temperatures of 25, 34 and 45°C and relative humidities of 32.4% and 63.5%. The effect of the storage conditions on the physical and chemical properties of the product were evaluated through total polyphenols, tannin and catechin determination, moisture content, macroscopic changes in powder appearance and X-ray difractograms. The results showed that high storage temperature and high relative humidity lead to increased degradation of the bioactive marker compounds. The shelf life of the spouted bed dried extracts was 276.2 days when the powder is stored at 25°C and 32.4% relative humidity.