《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》）
《本草》记载说：凡是天地间的万物，都具备阴阳属性，大小各自拥有不同的色类。探究其内在道理，都有相应的法象对应。因此，羽毛类的生物都生于阳而归属于阴；鳞甲介壳类的生物都生于阴而归属于阳。所以，空青效法木行，因此颜色青而主治肝脏；丹砂效法火行，因此颜色赤红而主治心脏；云母效法金行，因此颜色白而主治肺脏；雌黄效法土行，因此颜色黄而主治脾脏；磁石效法水行，因此颜色黑而主治肾脏。其余药材都可以以此类推，举例即可知晓。
旧有的说法认为药物配伍有一君、二臣、三佐、四使的原则，其意旨在于认为虽然药物众多，但主治疾病的重点专在于一味药，其他药物则按等级相互为用，大体上起到统制作用，这样才适宜，不必完全拘泥于此。所谓的“君”药，主导这一方剂，本来就没有固定的标准。《药性论》却以气味平和浓厚的药物定为君药，其次定为臣药和佐药，有毒性的药物多定为使药。这是错误的言论。假如想要攻破坚硬的积滞，大黄、巴豆这类药物难道不能成为君药吗？（出自《良方》）
医家中有人称上等药物为君，主要保养生命；中等药物为臣，主要保养性情；下等药物为佐使，主要治疗疾病。大体上，保养生命的药物宜多用君药，保养性情的药物宜多用臣药，治疗疾病的药物宜多用佐使药。这固然是用药的常规，但其奥妙并未完全阐明。大体上，药物治病各有侧重，主治的是君药，辅助主治的是臣药，与君药性质相反但能互相协助的是佐药，引导经气及引导治疗药物到达病所的是使药。例如治疗寒性疾病使用热性药物，那么热性药物就是君药，所有温热性质的药物都是辅助君药的，属于臣药。然而如果热性药物过于猛烈而产生危害，就需要少量使用寒凉药物来制约它，使热性药物不至于造成伤害，这就是所谓的“佐”。至于五脏六腑以及疾病所在的部位，各需要有引导作用的药物，使药力与病邪相遇，这就是所谓的“使”。其他病症也依此类推。这是用药的权衡法则。这两种义理在《素问》中均有记载，但读者未能察觉，因此特意阐明它们，以期待明智之人采纳。（出自《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*)