1，除去杂质和非药用部分，保持药材纯净；2，使药材干燥；3，通过加工，分出规格等级，便于按质论价；4，形成一定商品性状。加工药材一般都要达到形体完整，身干无杂，色泽好，不变气、味，有效成分破坏少等。

1, the removal of impurities and non medicinal herbs, keep clean; 2, the drying; 3, through processing, out of specification grade, easy payment; 4, the formation of certain commodity characters. In general, the processed materials should be complete in shape, dry in body dry, good in color, constant in gas and taste, and less in destruction of effective components.