用药处方有反佐之道者，此轩岐之法旨，治病之微权，有不可不明者。奈何后世医家，
每多假借以乱经常，不惟悖理于前，抑且遗害于后，是不可不辨也。观《内经》之论治曰∶
奇之不去则偶之，偶之不去则反佐以取之，所谓寒热温凉，反从其病也。此其义，盖言病有
微甚，亦有真假，先从奇偶以正治，正治不愈，然后用反佐以取之，此不得不然而然也。又
经曰∶微者逆之，甚者从之。又曰∶逆者正治，从者反治。此谓以寒治热，以热治寒，逆其
病者，谓之正治；以寒治寒，以热治热，从其病者，谓之反治。如以热治寒而寒拒热，则反
佐以寒而入之；以寒治热而热拒寒，则反佐以热而入之，是皆反佐之义，亦不得不然而然也
。又经曰∶热因寒用，寒因热用。王太仆注曰∶热因寒用者，如大寒内结，当治以热，然寒
甚格热，热不得前，则以热药冷服，下嗌之后，冷体既消，热性便发，情且不违，而致大益
，此热因寒用之法也。寒因热用者，如大热在中，以寒攻治则不入，以热攻治则病增，乃以
寒药热服，入腹之后，热气既消，寒性遂行，情且协和，而病以减，此寒因热用之法也。凡
此数者，皆《内经》反佐之义。此外，如仲景治少阴之利，初用白通汤，正治也。继因有烦
而用白通加猪胆汁汤，反佐也。其治霍乱吐痢，脉微欲绝者，初用四逆汤，正治也。继因汗
出小烦，而用通脉四逆加猪胆汁汤，反佐也。又如薛立斋治韩州同之劳热，余尝治王蓬雀之
喉痹，皆其法也。
若今诸家之所谓反佐者则不然，姑实时尚者道其一二以见之。如近代之所宗所法者，谓
非丹溪之书乎？观丹溪之治吞酸证，必以炒黄连为君，而以吴茱萸佐之；其治心腹痛证，谓
宜倍加山栀子而以炒干姜佐之。凡此之类，余不解也。夫既谓其热，寒之可也，而何以复用
干姜、茱萸？既谓其寒，热之可也，而何以复用黄连、栀子？使其病轻而借以行散，即或见效
，岂曰尽无；使其病重，人则但见何以日甚，而不知犯寒犯热，自相矛盾，一左一右，动皆
掣肘，能无误乎？矧作用如此，则其效与不效，必其莫知所因，而宜热宜寒，亦必从违奚辨
。此其见有不真，故持两可，最是医家大病，所当自反而切戒者也。
或曰∶以热导寒，以寒导热，此正得《内经》反佐之法。人服其善，子言其非。何其左
也？余曰∶此法最微，此用最妙，子亦愿闻其详乎？当为再悉之。夫反佐之法，即病治之权也
。儒者有经权，医者亦有经权。经者，日用之常经，用经者，理之正也；权者，制宜之权变
，用权者，事之暂也。此经权之用，各有所宜，诚于理势有不得不然，而难容假借者也。药
中反佐之法，其亦用权之道，必于正经之外，方有权宜，亦因不得不然，而但宜于暂耳，岂
果随病处方，即宜用乎？然则何者宜反？何者不宜反？盖正治不效者，宜反也。病能格药者，
宜反也。火极似水者，宜反也。寒极反热者，宜反也。真以应真，假以应假，正反之道，妙
用有如此也。设无格拒假证，自当正治，何以反为？不当权而用权，则悖理反常，不当反而
佐反，则致邪失正。是乌可以混用耶？常观轩岐之反佐，为创经权之道也；后世之反佐，徒
开杂乱之门也。至其变也，则泾渭不分者以之，模糊疑似者以之，寒热并用者以之，攻补兼
施者以之，甚至广络妄投，十寒一暴，无所不谬，皆相借口，此而不辨，医乎难矣。于戏！
斯道失真，其来已久，安得愿闻精一者，与谈求本之道哉！是不能无望于后人也，因笔识其
愚昧。以上仲景治法载《伤寒论》。薛立斋治韩州同按在虚损门。余治王蓬雀按在喉痹门。
用药处方中运用反佐的方法，这是黄帝、岐伯医学理论的核心宗旨，是治疗疾病时微妙而关键的权变手段，其中道理不可不明了。为何后世医家，常常假借这一方法扰乱常规，不仅在前理上违背常道，而且给后人留下危害，这是不可不辨别的。观察《内经》关于治疗的论述说：用奇方（单数药味或单一性质）无效则改用偶方（双数药味或复合性质），用偶方无效则采用反佐法来取得疗效，所谓寒热温凉，顺应病势而治。这里的含义，大概是指病情有轻微与严重之分，也有真象与假象之别，先通过奇偶之法进行正治，如果正治无效，然后才使用反佐法来取效，这是不得不如此的情况。又经文说：病情轻微的逆其病性治疗，病情严重的顺其病性治疗。又说：逆其病性的是正治，顺其病性的是反治。这指的是用寒药治热病，用热药治寒病，逆着病邪性质的，称为正治；用寒药治寒病，用热药治热病，顺着病邪表现的，称为反治。例如用热药治寒病但寒邪拒斥热药，则反佐以寒药引导进入；用寒药治热病但热邪拒斥寒药，则反佐以热药引导进入，这些都是反佐的含义，也是不得不如此的情况。又经文说：热药冷服，寒药热服。王冰注解说：热因寒用，比如体内有大寒凝结，应当用热药治疗，然而寒邪太盛格拒热药，使热药无法前行，就用热药冷服，咽下之后，冷体消散，热性便发作，病情不违逆，从而获得大益，这就是热因寒用的方法。寒因热用，比如体内有大热，用寒药攻治则药力不入，用热药攻治则病情加重，于是用寒药热服，入腹之后，热气消散，寒性遂行，病情协和，从而减轻，这就是寒因热用的方法。凡此种种，都是《内经》中反佐的含义。此外，如张仲景治疗少阴病的下利，起初用白通汤，这是正治。后来因为出现烦躁症状，改用白通加猪胆汁汤，这是反佐。他治疗霍乱吐泻，脉微欲绝者，起初用四逆汤，这是正治。后来因为出汗且轻微烦躁，改用通脉四逆加猪胆汁汤，这是反佐。又如薛立斋治疗韩州同的劳热，我曾经治疗王蓬雀的喉痹，都是运用了这种方法。
至于如今各家所谓的反佐法就不是这样了，姑且列举当时流行的几种情况来展示。如近代所推崇效法的，难道不是朱丹溪的书吗？看丹溪治疗吞酸证，必定以炒黄连为君药，而以吴茱萸为佐药；他治疗心腹痛证，说应当加倍使用山栀子而以炒干姜为佐药。凡此类情况，我不理解。既然说是热证，用寒药是可以的，那为什么还要复用干姜、吴茱萸？既然说是寒证，用热药是可以的，那为什么还要复用黄连、山栀子？如果病情轻浅而借它们来行散，或许能见效，难道说完全没有错误吗？如果病情沉重，人们只看到为何日益加重，却不知道犯了寒热自相矛盾的错误，一左一右，动辄掣肘，能没有失误吗？况且作用如此，那么有效与无效，必然让人不知原因所在，该用热还是该用寒，也必然难以分辨顺逆。这是因为见解不真切，所以持两可态度，这最是大医家的弊病，应当自我反省并深切戒除的。
有人说：用热药引导寒邪，用寒药引导热邪，这正是得到《内经》反佐的方法。人们称赞他善于此道，您却说不对。怎么这么偏执呢？我说：这种方法最微妙，应用最精妙，您也希望听详细解释吗？我将为您详尽说明。夫反佐之法，是治病时的权变之道。儒者有经权和权变，医者也有经权和权变。经，是日常遵循的常道，运用经，是理之正；权，是制宜的权变，运用权，是事之暂。这种经权的应用，各有适宜之处，确实于理势上有不得不然的地方，难以容许假借滥用。药物中的反佐之法，也是用权的道理，必须在正经之外，才有权宜之计，也是因为不得不然，只适宜于暂时使用，难道真的是随病处方就适宜使用吗？那么什么适宜反佐？什么不适宜反佐？大概是正治无效者，适宜反佐。病性能格拒药物者，适宜反佐。火极似水者，适宜反佐。寒极反热者，适宜反佐。真证应对真治，假证应对假治，正反之道，妙用达到如此地步。假设没有格拒和假证，自然应当正治，为什么要反治？不当用权而用权，则违背常理反乎正常；不当反佐而反佐，则导致邪气胜而正气失。这怎么能混用呢？经常观察黄帝、岐伯的反佐，是创立经权之道的；后世的反佐，只是开启了杂乱之门。到了它的流变，混淆是非者用它，模糊疑似者用它，寒热并用者用它，攻补兼施者用它，甚至广泛胡乱投药，十次受寒一次暴晒，无所不谬，都以此为借口，如果不辨别这些，做医生就难了。唉！这门学问失真，由来已久，哪里能得到愿意听闻精纯之道的人，与他谈论求本的道理呢！因此不能不寄希望于后人，于是写下这些记录我的愚昧。以上张仲景的治疗法则记载于《伤寒论》。薛立斋治疗韩州同按语在虚损门。我治疗王蓬雀按语在喉痹门。
The method of using counter-assistance (Fan Zuo) in prescribing medication is the core principle of the medical theories of Huangdi and Qibo, a subtle and critical adaptive strategy in treating diseases, the rationale of which must be clearly understood. Why is it that later generations of physicians often borrow this method to disrupt established norms? Not only does this contradict logic initially, but it also leaves harmful consequences for posterity; thus, it is imperative to distinguish between correct and incorrect applications. Observing the discussions on treatment in the *Neijing* (Classic of Internal Medicine): "If an odd formula (Qi, referring to formulas with single-natured or fewer herbs) fails, use an even formula (Ou, referring to formulas with combined natures or more herbs); if an even formula fails, use counter-assistance to achieve the cure." This refers to cold, heat, warmth, and coolness treatments that follow the disease's manifestation. The meaning here implies that diseases vary in severity and may present true or false symptoms. One should first employ standard treatment (Zheng Zhi) via odd or even formulas; if standard treatment proves ineffective, then counter-assistance is employed. This is a necessary adaptation. Furthermore, the classics state: "For mild conditions, treat contrary to the disease nature; for severe conditions, treat in accordance with the disease nature." It also states: "Treating contrary to the disease nature is called Standard Treatment (Zheng Zhi); treating in accordance with the disease nature is called Counter-Treatment (Fan Zhi)." This means using cold medicines to treat heat diseases and hot medicines to treat cold diseases, opposing the pathogen's nature, is termed Standard Treatment; whereas using cold medicines to treat cold diseases and hot medicines to treat heat diseases, following the disease's apparent nature, is termed Counter-Treatment. For instance, when treating cold with hot medicine but the cold pathogen rejects the heat, one adds a small amount of cold medicine as counter-assistance to facilitate entry; when treating heat with cold medicine but the heat pathogen rejects the cold, one adds a small amount of hot medicine as counter-assistance to facilitate entry. These are all meanings of counter-assistance, representing necessary adaptations. Additionally, the classics say: "Hot medicines taken cold, cold medicines taken hot." Wang Bing commented: "Hot due to cold usage" refers to cases like severe internal cold accumulation requiring hot treatment. However, if extreme cold repels hot medicine preventing its action, the hot medicine should be taken cold. After swallowing, once the cold temperature dissipates, the hot therapeutic property activates. The patient's condition remains uncontradicted, yielding great benefit. This is the method of 'hot due to cold usage.' "Cold due to hot usage" refers to cases like severe internal heat where cold attack fails to penetrate and hot attack worsens the disease. Thus, cold medicine is taken hot. After entering the abdomen, once the heat dissipates, the cold therapeutic property acts. The condition harmonizes, and the disease diminishes. This is the method of 'cold due to hot usage.' All these instances illustrate the concept of counter-assistance in the *Neijing*.
Furthermore, Zhang Zhongjing treated diarrhea associated with Shaoyin syndrome by initially using Baitong Decoction (Bai Tong Tang), which is standard treatment. Later, due to the appearance of irritability, he switched to Baitong Decoction plus Porcine Bile and Pig Gallbladder (Bai Tong Jia Zhu Dan Ye Tang), which is counter-assistance. In treating Huoluan (cholera-like syndrome) with vomiting and diarrhea and a faint pulse nearing extinction, he initially used Sini Decoction (Si Ni Tang), which is standard treatment. Later, due to sweating and slight irritability, he used Tongmai Sini Decoction plus Porcine Bile and Pig Gallbladder (Tongmai Sini Jia Zhu Dan Ye Tang), which is counter-assistance. Similarly, Xue Lizhai treated Han Zitong's consumption fever, and I treated Wang Pengque's throat bi (sore throat/swelling), both employing this method.
However, the so-called counter-assistance practiced by various schools today is different. Let us briefly examine some contemporary popular examples. The works highly revered in recent times belong to Zhu Danxi. In treating acid regurgitation, Zhu Danxi invariably used Stir-fried Coptis Rhizome (Chao Huanglian, 炒黄连) as the sovereign herb, assisted by Evodia Fruit (Wuzhuyu, 吴茱萸). In treating heart and abdominal pain, he advocated doubling the dose of Gardenia Fruit (Shanzhizi, 山栀子) and assisting it with Stir-fried Dried Ginger (Chao Ganjiang, 炒干姜). I do not understand such practices. If the condition is indeed heat, cold medicine suffices; why add Dried Ginger and Evodia? If the condition is indeed cold, hot medicine suffices; why add Coptis and Gardenia? If the disease is mild and these are borrowed for their dispersing properties, efficacy might be seen, yet errors could still exist. If the disease is severe, patients will only observe worsening symptoms daily, unaware that they are suffering from contradictory cold-heat interventions, pulling in opposite directions, leading to constant hindrance and inevitable mistakes. Moreover, with such complex actions, determining efficacy becomes difficult, and distinguishing whether heat or cold is appropriate becomes ambiguous. This stems from unclear insight, leading to indecision, which is a major flaw in medical practice and should be self-reflected upon and strictly avoided.
Some argue: "Using hot to guide cold, and cold to guide heat, this perfectly aligns with the *Neijing*'s method of counter-assistance. People praise his skill, yet you deny it. How biased are you?" I reply: "This method is subtle and its application exquisite. Do you wish to hear the details? I shall explain thoroughly. The method of counter-assistance is an adaptive strategy in treatment. Confucians speak of constant principles (Jing) and adaptive measures (Quan); physicians likewise have Jing and Quan. Jing refers to daily constant laws; applying Jing is correct reasoning. Quan refers to situational flexibility; applying Quan is temporary adjustment. Both have their appropriate uses, grounded in necessity, leaving no room for arbitrary borrowing. The use of counter-assistance in herbs is also a form of Quan. It applies only outside standard principles, serving as a temporary measure necessitated by circumstances. It is not suitable for every prescription. So, what requires counter-assistance and what does not? Generally, those unresponsive to standard treatment require counter-assistance. Those whose pathology repels medication require counter-assistance. Cases of extreme fire resembling water require counter-assistance. Cases of extreme cold resembling heat require counter-assistance. True conditions are treated truly, false conditions are treated falsely. The interplay of opposition and conformity offers such profound utility. Assuming there is no pathological rejection or false presentation, standard treatment should naturally be used; why resort to counter-treatment? Using adaptability when inappropriate violates logic and normalcy; using counter-assistance when inappropriate leads to pathogen dominance and loss of healthy qi. How can these be mixed indiscriminately? Historically, Huangdi and Qibo introduced counter-assistance to establish the doctrine of Jing and Quan; later generations' misuse has merely opened doors to chaos. Its deviations include confusing right and wrong, blurring distinct symptoms, combining cold and heat indiscriminately, and mixing attacking and tonifying methods. Some even prescribe wildly, alternating ten doses of cold with one of heat, committing numerous errors while using this as an excuse. Without distinguishing these, practicing medicine becomes nearly impossible. Alas! The distortion of this doctrine has existed for a long time. Where can one find someone willing to listen to pure truths and discuss the way of seeking the root? Therefore, I place my hope in future generations and record these reflections on my own limited understanding. The above treatment methods of Zhang Zhongjing are recorded in the *Shanghan Lun* (Treatise on Cold Damage). Xue Lizhai's treatment of Han Zitong is noted in the Consumption section. My treatment of Wang Pengque is noted in the Throat Bi section."