Activated charcoal, used for decolorization and purification of crude protease, was regenerated by treatment six times with acetone/water (40:60 v/v), followed by drying. This multistage leaching followed the leaching equation adapted to multistage leaching. The regenerated charcoal was nearly as effective as fresh charcoal in decolorization and purification of crude protease, but only after drying. List of symbols: c*, equilibrium solute concentration (w/v) in liquid; cs, solute concentration in solid phase (w/w); F, interfacial area between solid and liquid phases; k, rate constant for leaching equation; v, volume of liquid per unit weight of adsorbent (solid phase).