Background: Our experiment based on the research and the choice optimal fomula containing insoluble component Glucomannan extracted from Amorphophallus paeoniifolius species. The aim of this study was to evaluate the stability of granules for oral suspension containing Glucomannan. Materials and method: The products were stored in sealed aluminium package at room condition (250C, RH 60% - 75%) for 6 months or at accelerated condition (40 ± 20C, RH 75 ± 5%) for 4 months. After storing, evaluating the physico-chemical characteristics of granules for oral suspension containing Glucomannan such as α – angle, moisture content... Results: The results showed that the products were stable at the above conditions about appearance, moisture content, dispersion state in 3 minutes, level of phase separation, residue ratio after 24 hours according to the fourth edition of Vietnamese Pharmacopoeia. Conclusion: Granules for oral suspension containing Glucomannan were stable during research time. Key words: granule, oral suspension, Glucomannan, stability