Among the vast array of ingredients used, some cannot be taken directly without proving poisonous, some cannot be stored without changing in nature, and some must be refined of various impurities and unusable portions, so that the majority require some kind of processing before use.
琳琅滿目的藥材中，有的含有毒性，不能直接服用，有的易變質，不能久藏，有的則需除去雜質與不適用的部位，因此大多需經一定的加工。