The alkaline fading of crystal violet (CV) is accelerated by using a W/O microemulsion of H2O/AOT/ethane under supercritical conditions. The rate of fading can be changed by three orders of magnitude with operating pressure and the molar ratio of water to AOT. The highest rate of CV fading observed is larger by a factor of 100 or more compared to those reported so far in the literature. The structure of AOT molecules and the type of interior water molecules seem to account for the rate enhancement with an increase in the H2O/AOT molar ratio. It is suggested that the intermicellar and AOT-ethane interactions are of significance for the promotion effect of pressure.