药性阴阳论
夫药有寒热温凉之性，酸苦辛咸甘淡之味，升降浮沉之能，浓薄轻重之用。或气一而味
殊，或味同而气异，合而言之，不可混用。分而言之，各有所能。本乎天者亲上，本乎地者
亲下。轻清成象，重浊成形。清阳发腠理，浊阴走五脏。清中清者，营养精神。浊中浊者，
坚强骨髓。辛甘发散为阳，酸苦涌泄为阴。气为阳，气浓为阳中之阳，气薄为阳中之阴。薄
则发泄，浓则发热。味为阴，味浓为阴中之阴，味薄为阴中之阳。薄则疏通，浓则滋润。升
降浮沉之辨，豁然贯通，始可以言医，而司人命矣。人徒知药之神者，乃药之力也。殊不知
乃用药之力也。人徒知辨真伪识药之为难，殊不知分阴阳用药之为尤难也。
夫用药者，当知标本。以身论之，外为标，内为本；气为标，血为本；阳为标，阴为本；
六腑属阳为标，五脏属阴为本。以病论之，先受病为本，后传变为标。凡治病者，先治其
本，后治其标。虽有数病，靡弗去矣。若先治其标，后治其本，邪气滋甚，其病益坚。若有
中满，无问标本，先治其满，谓其急也。若中满后有大小便不利，亦无问标本，先治大小便，
次治中满。谓尤急也。又如先病发热，后病吐泻，饮食不下，则先定呕吐，后进饮食，方
兼治泻。待元气稍复，乃攻热耳。此所谓缓则治其本，急则治其标也。除大小便不利及中满
吐泻之外，皆先治其本，不可不知也。假令肝受心火之邪，是从前来者为实邪，实则泻其子，
然非直泻其火，入肝经药为之引。用泻火为君，是治实邪之病也。假令肝受肾邪，是从后
来者为虚邪。虚则补其母，入肾经药为之引，用补肝药为君是也。标本已得，邪气乃服。医
之神良，莫越乎此。
药性阴阳论
药物的性质有寒、热、温、凉四种，味道有酸、苦、辛、咸、甘、淡六种，功效有升、降、浮、沉四种趋向，作用有浓、薄、轻、重的区别。有的药物气味相同但味道不同，有的药物味道相同但气味不同，综合起来看，不能混淆使用；分开来说，各自有其特定的功能。源于天（气）的药物趋向于上部，源于地（味）的药物趋向于下部。质地轻清的构成象，质地重浊的构成形。清阳之气发散于腠理（皮肤肌肉之间的间隙），浊阴之气走注于五脏。清中之清者，滋养精神；浊中之浊者，坚固骨髓。辛味和甘味具有发散作用，属于阳；酸味和苦味具有涌吐和泄下的作用，属于阴。气属阳，气浓厚者为阳中之阳，气淡薄者为阳中之阴。气淡薄则能发泄，气浓厚则能发热。味属阴，味浓厚者为阴中之阴，味淡薄者为阴中之阳。味淡薄则能疏通，味浓厚则能滋润。对于升、降、浮、沉的辨别，如果能豁然贯通，才可以谈论医学，担当救死扶伤的重任了。人们只知道药物的神奇之处，那是药物的力量。却不知道这其实是运用药物的力量。人们只知道辨别真伪、识别药物很难，却不知道分辨阴阳来用药更加困难。
运用药物的人，应当懂得标本的概念。从人体本身来说，外部为标，内部为本；气为标，血为本；阳为标，阴为本；六腑属阳为标，五脏属阴为本。从疾病来说，先受病的是本，后传变的是标。凡是治病，先治其本，后治其标。即使有多种疾病，没有不消除的。如果先治其标，后治其本，邪气会更加旺盛，病情会更加顽固。如果有中满（脘腹胀满）的症状，无论标本如何，先治疗中满，因为这是急症。如果中满之后出现大小便不利，也无论标本如何，先治疗大小便不利，然后再治疗中满，因为这更为紧急。又比如先病发热，后病呕吐腹泻，饮食不下，那么先止住呕吐，然后进食，再兼治腹泻。等到元气稍微恢复，再去攻治热邪。这就是所谓的“缓则治其本，急则治其标”。除了大小便不利及中满、呕吐、腹泻之外，其他情况都是先治其本，这一点不可不知道。假如肝受到心火的邪气侵袭，这是从前来者为实邪，实证应当泻其子（实则泻其子），然而不是直接泻火，而是用入肝经的药物作为引经药。以泻火药为君药，这是治疗实邪的方法。假如肝受到肾邪的侵袭，这是从后来者为虚邪，虚证应当补其母（虚则补其母），用入肾经的药物作为引经药，以补肝药为君药，就是这样。标本得当，邪气自然服从。医生之神妙良善，没有超过这个原则的了。
On the Yin and Yang of Drug Properties
Drugs possess natures of cold, heat, warm, and cool; flavors of sour, bitter, pungent, salty, sweet, and bland; functional tendencies of ascending, descending, floating, and sinking; and applications of density, thinness, lightness, and heaviness. Some drugs share the same qi (vital energy/aroma) but differ in flavor, while others share the same flavor but differ in qi. Taken together, they must not be used interchangeably; taken separately, each has its specific efficacy. Those derived from heaven (qi) tend toward the upper part; those derived from earth (flavor) tend toward the lower part. Light and clear substances form images (functional aspects), while heavy and turbid substances form shapes (structural aspects). Clear yang disperses into the couli (interstices of skin and muscle), while turbid yin travels to the five zang organs. The clearest among the clear nourishes the spirit (shen); the most turbid among the turbid strengthens the bone marrow. Pungent and sweet flavors have a dispersing action and belong to yang; sour and bitter flavors have an inducing-vomiting and purgative action and belong to yin. Qi belongs to yang: dense qi is yang within yang, while thin qi is yin within yang. Thin qi causes exfoliation/dispersal, while dense qi generates heat. Flavor belongs to yin: dense flavor is yin within yin, while thin flavor is yang within yin. Thin flavor promotes unblocking/circulation, while dense flavor provides moistening/nourishment. Only when one clearly comprehends the distinctions among ascending, descending, floating, and sinking can one speak of medicine and assume responsibility for human life. People only know that the miraculous effect of drugs lies in the power of the drugs themselves. They do not realize that it actually lies in the power of how drugs are applied. People only know that distinguishing authenticity and identifying drugs is difficult; they do not realize that distinguishing yin and yang to guide drug application is even more difficult.
Those who apply drugs must understand the concepts of root (ben) and branch (biao). In terms of the body, the exterior is the branch, and the interior is the root; qi is the branch, and blood is the root; yang is the branch, and yin is the root; the six fu organs, belonging to yang, are the branch, and the five zang organs, belonging to yin, are the root. In terms of disease, the condition first contracted is the root, and subsequent transformations or transmissions are the branch. In treating any disease, one should first treat the root and then the branch. Even if multiple diseases exist, none will remain untreated. If one treats the branch first and the root later, the pathogenic factors will become more vigorous, and the disease will become more entrenched. However, if there is abdominal fullness (zhong man), regardless of root or branch, one must first treat the fullness because it is an urgent condition. If, following abdominal fullness, there is difficulty in urination or defecation, regardless of root or branch, one must first address the urinary or fecal obstruction, and then treat the abdominal fullness, as this is even more urgent. For example, if a patient first suffers from fever, followed by vomiting and diarrhea with inability to eat, one should first stop the vomiting, allow food intake, and then concurrently treat the diarrhea. Once the primordial qi (yuan qi) has slightly recovered, one may then attack the heat. This is what is meant by "treat the root when the condition is slow/stable, and treat the branch when the condition is urgent." Except for difficulties in urination/defecation, abdominal fullness, vomiting, and diarrhea, one should always treat the root first; this must not be ignored. Suppose the liver is affected by pathogenic fire from the heart; this is an excess pathogen coming from the preceding organ (Wood generating Fire, here implying the mother-son relationship where Heart is the son of Liver in some contexts, or specifically referring to the Five Elements generation sequence where Liver Wood generates Heart Fire, so Heart is the 'son' of Liver? Note: The text says "from front" which usually implies generation sequence. In Five Elements, Liver (Wood) generates Heart (Fire). So Heart is the son of Liver. If Liver is affected by Heart Fire, it's "coming from behind" in generation? Wait. Standard TCM theory: "From the one that generates me is deficiency pathogen (Xu Xie), from the one I generate is excess pathogen (Shi Xie)." The text says "Liver receives Heart Fire... from front... excess". Let's stick to the text's logic: "From front" = Excess. "Excess requires draining the son". Text says "drain its son". If Liver is the subject, and it receives Heart Fire, and it's treated by draining the son... wait. If Liver is the diseased organ, and it's an excess pattern caused by Heart, standard theory might differ. However, I must translate the text faithfully. Text: "Liver receives Heart Fire... from front... excess... drain the son". I will translate literally based on the provided text's internal logic.) ...this is an excess pathogen originating from the preceding stage. In excess patterns, one drains the "son" organ. However, this does not mean directly draining the fire, but rather using herbs entering the Liver meridian as guiding agents (yin jing yao). Using fire-draining herbs as the sovereign drug constitutes the treatment of excess pathogenic conditions. Suppose the liver is affected by pathogenic factors from the Kidney; this is a deficiency pathogen originating from the subsequent stage. In deficiency patterns, one tonifies the "mother" organ. Using herbs entering the Kidney meridian as guiding agents, and using liver-tonifying herbs as the sovereign drug, is the correct approach. When the root and branch are properly addressed, the pathogenic factors submit. There is no greater principle for the divine excellence of a physician than this.