In this study we found no significant effect on benign prostatic hypertrophy due to megestrol using standard clinical criteria. However, there is evidence using urinary drop spectrometer data which makes one suspect that megestrol does have a positive effect. If there is an effect, it is apparently so small as to be undetectable using the clinical protocol of this investigation. Since the urodynamic evidence does indicate a possibility of a positive effect, it appears reasonable to investigate further using a different protocol - perhaps a higher dosage and/or a more controlled test population.