《本草》云∶凡天地万物，皆有阴阳，大小各有色类。寻究其理，并有法象。故羽毛之类皆
生于阳而属于阴，鳞介之类皆生于阴而属于阳。所以空青法木，故色青而主肝；丹砂法火，故色
赤而主心；云母法金，故色白而主肺；雌黄法土，故色黄而主脾；磁石法水，故色黑而主肾。余
皆以此推之，例可知也。
旧说药用一君、二臣、三佐、四使之说，其意以谓药虽众，主病者专在一物，其他则节级相
为用，大略相统制，如此为宜，不必尽然。所谓君者，主此一方，固无定本也。《药性论》乃以
众药之和浓者定为君，其次为臣为佐，有毒者多为使。此谬论也。设若欲破坚积，大黄、巴豆辈
岂得不为君也？（《良方》）
医家有谓上药为君，主养命；中药为臣，主养性；下药为佐使，主治病。大抵养命之药宜多
君，养性之药宜多臣，治病之药宜多佐使。此固用药之经，然其妙则未尽也。大抵药之治病，各有
所主，主治者君也，辅治者臣也，与君相反而相助者佐也，引经及引治病之药至于病所者使也。
如治寒病用热药，则热药君也，凡温热
之药皆辅君者也，臣也。然或热药之过甚而有害也，须少用寒凉药以监制之，使热药不至为害，
此则所谓佐也。至于五脏六腑及病之所在，各须有引导之药，使药与病相遇，此则所谓使也。余
病准此。此用药之权也。二义《素问》俱有，而读者不察，故特发明之，以俟夫智者采云。
（《柏斋二一书》）
The *Bencao* (Materia Medica) states: All things in heaven and earth possess Yin and Yang attributes, and each has its own distinct categories of size and color. Investigating their principles reveals corresponding "Fa Xiang" (symbolic correspondences). Therefore, creatures with feathers are born from Yang but belong to Yin; creatures with scales or shells are born from Yin but belong to Yang. Thus, Kongqing (Azure Mineral) corresponds to Wood, hence its green color and affinity for the Liver; Cinnabar (Dansha) corresponds to Fire, hence its red color and affinity for the Heart; Mica (Yunmu) corresponds to Metal, hence its white color and affinity for the Lungs; Orpiment (Cihuang) corresponds to Earth, hence its yellow color and affinity for the Spleen; Magnetite (Cishi) corresponds to Water, hence its black color and affinity for the Kidneys. The rest can be deduced by this analogy.
Old theories propose that herbal prescriptions follow a structure of one Sovereign (Jun), two Ministers (Chen), three Assistants (Zuo), and four Guides (Shi). The intent is that although many herbs are used, the primary action against the disease lies in one specific herb, while others serve subordinate roles in a hierarchical manner, providing general control. This is appropriate, though not absolute. The role of the "Sovereign" herb, which leads the prescription, does not have a fixed standard. *Yaoxing Lun* (Treatise on Drug Properties) incorrectly defines the Sovereign as the herb with the mildest and most concentrated nature, followed by Ministers and Assistants, with toxic herbs often serving as Guides. This is a fallacy. If the goal is to break down hard accumulations, how could Da Huang (Rhubarb Rhizome) or Ba Dou (Croton Seed) not serve as the Sovereign? (*Liang Fang*)
Some physicians claim that superior herbs are Sovereigns, primarily nourishing life; medium herbs are Ministers, primarily nourishing nature/temperament; and inferior herbs are Assistants and Guides, primarily treating disease. Generally, herbs for nourishing life should predominantly feature Sovereigns; those for nourishing temperament, Ministers; and those for treating disease, Assistants and Guides. While this is a general principle of medication, it does not fully capture its subtleties. Fundamentally, herbs treat diseases with specific focuses: the primary agent is the Sovereign; the secondary agent is the Minister; the herb that opposes the Sovereign's nature yet assists its function is the Assistant; and the herb that guides the meridian qi and directs the therapeutic agents to the site of the disease is the Guide. For example, when treating a Cold disease with Hot herbs, the Hot herb is the Sovereign, and all warming herbs act as Ministers assisting the Sovereign. However, if the Hot herbs are too intense and harmful, a small amount of Cooling herbs must be added to restrain them, preventing harm from the Heat. This is the role of the Assistant. Regarding the Five Zang and Six Fu organs and the location of the disease, guiding herbs are required to ensure the medicinal force encounters the pathogen. This is the role of the Guide. Other conditions follow this logic. This represents the flexibility in prescribing. Both interpretations exist in *Suwen* (Basic Questions), but readers often overlook them. Therefore, they are clarified here for the wisdom of intelligent practitioners to adopt. (*Baizhai Er Yi Shu*)