In order to control the release rate of slightly water soluble medicine by using the solid dispersion (SD) method, the SD was prepared with a water soluble polymer and the slightly soluble medicine, and the medicine release from the solid dispersion granules was studied. The SD granules were prepared by the evaporation of ethanol after dissolving into ethanol a slightly water soluble medicine (flurbiprofen (FP)) and soluble polymers (hydroxypropyl cellulose (HPC)). HPC has four grades of molecular weight. The release rate of FP from SD was measured by the rotating basket method (JP XII).The release rate of FP from the SD granules was markedly larger than that from FP powder, and it was larger with a lower HPC molecular weight. It is speculated that these results were mainly based on the molecular dispersion state of FP and HPC in SD.