To obtain a specific pharamcological effect, herbal medicines are processed based on the principle of traditional korean medicines. The problem in drug processing is the variety of methods, technics, and drug quality. In order to establish the base of standardization of processing methods, some herbal medicines(Evodiae Fructus, Scutellariae Radix, Astragali Radix, Zingiberis Rhizoma, Dioscoreae Radix, Aconiti Radix) were processed and studied the change a color tone of processed and unprocessed herbal medicines. The color tone(value and chroma) of these herbal medicines were changed after processing.