辨病之难，不难于真正，而难于疑似。治病之难，不难于正逆，而难于反从。盖积在中，实也，甚则默默不
欲语，肢体不欲动，或眩晕昏花，泄泻不时，皆大实有羸状也。正如食而过饱，反倦怠嗜卧也。脾胃损伤，虚也，
甚则胀满而食不得入，气不得舒，便不得利，皆至虚有盛候也。正如饥而过时，反不思食也。脾胃虚寒，真阴症
也，阴盛之极，往往格阳，面红目赤，口舌破烂，手扬足掷，语言错乱，有似乎阳也。正如严冬惨肃，而水泽坚
冰，坚为阳刚之象也。邪热未解，真阳证也，阳盛之极，往往发厥，厥则口鼻无气，手足逆冷，有似乎阴也。正
如盛夏炎灼，林木流津，津为阴柔之象也。所以前人有云∶实见羸状，虚得盛候，误在补泻。阴症似阳，阳症似
阴，毙于温凉。可不辨乎？其实亦易明，如真寒者厥冷、呕吐、腹痛、泄泻、小便清频，即有热发，必欲得衣，
脉沉小或迟而濡，目得热气则少瘥；真热者烦
躁喘渴，声音壮厉，大便秘结，小水赤涩，发热掀衣，脉滑数或大而有力，目痛畏光与热；假寒者身虽冷却恶衣，
便热且难，心烦喜饮，上下气出，鼻秽，脉迟有力或沉而鼓激；假热者虽面赤身炽热，衣被不撤而神静，语虽谵
妄，声息则微，或虚狂起倒，禁之则止，或蚊迹花斑而淡红细碎，或喜冷水而所啜不多，或大便不解而小水多利，
脉虽数而濡，或浮大无根及芤弦断续；真虚者色惨形疲，精衰气怯，自汗不收，二便不禁，脉弱无神；真实者内
结脏腑，外闭经络，气壅不行，血留为祸，脉形俱盛；假虚者状似羸而脉病争强，假实者病虽盛而正气大衰。治
真虚者补，真实者攻，真寒者温，真热者凉，是谓正、逆。假寒者清其内热，内清则浮阴退舍。假热者温其真阳，
中温则虚火归原。假虚者正气既损，当直去其邪，邪去则身安。假实者邪气虽盛，当兼补正，正存则不致大患。
且补中自有攻意，世未有正气复而邪不退者，亦未有正竭而命不倾者，万不得已，亦宜从轻从缓，寓战于守。斯
可矣，是谓反、从。要之，能胜攻者固实证，实者多热，药虽寒无虑。不能胜攻者便是虚，虚者多寒，药非温热
恐呼吸变生，转应无及。是故疑似之症，神色不足凭，当参以脉理。脉又不足凭，当察其禀受，喜温喜凉与夫痰、
汗、便、溲，恶寒恶热暨病之久新，药之误否，然后下以汤剂，虽不中，不远矣。若乃塞因塞用、通因通用、热
因热用、寒因寒用、用热远热、用寒远寒者，如脾虚作胀，治以参术，脾得补而胀自消。肾虚气逆上，治以五味
子，肾得补而气归元，逆满自平。塞因塞用也。伤寒挟热下利，或中有燥粪，用调胃承气下之乃安。滞下不利，
用芍药汤通之而愈。通因通用也。药本寒也，而反佐之以热，药本热也，而反佐之以寒，俾无拒格之患，经所谓
必先其所主而伏其所因，其始则异，其终则同，
热因热、寒因寒用也。寒病宜投热药，热病宜投寒药，仅使中病，勿过用焉，过用转恐为药伤矣，经所云久而增
气，物化之常，气增日久，夭之由也。用热远热、寒远寒也。已上诸法，亦从治之大凡，扩而充之，惟在明良者
触类而已。故曰病无常形，医无常方，药无常品，顺逆进退存乎其时，君臣佐使存乎其用，圣神工巧存乎其人。
彼自用自专以正逆邪，适逢真病当不大谬。一旦临疑似之症，治应反从，若涉大海，莫知津涯，几微之间，生杀
凛然。况是假虚之病不多见，而假实之症恒有，假寒之误通解，而假热之误不可救，一剂入口，五内迸裂。人非
木石，言亦寒心。然又有反从而逆正，假病医至真病者，皆疑似之害之也。皓首穷经，不免一失，哀哉！故谨编
其辨病治病之至难者，以告后人，仁以为己任者，当必引为同心。
辨别疾病的难点，不在于识别真正的病症，而在于区分相似（疑似）的病症。治疗疾病的难点，不在于处理顺证与逆证，而在于应对“反治”与“从治”。
邪气积聚在体内，属于实证，严重时会出现沉默寡言、不想说话，肢体不愿活动，或者眩晕眼花、不时泄泻等症状，这都是大实之证却呈现出虚弱的表象。这就像吃得太饱，反而感到倦怠嗜睡一样。
脾胃受损，属于虚证，严重时会出现腹胀满闷、食物无法进入、气息不能舒展、大小便不通利等症状，这都是极度的虚弱却呈现出亢盛的假象。这就像饥饿过了头，反而不想吃东西一样。
脾胃虚寒，属于真阴证，阴寒之气盛极，往往会导致格阳（阴盛格阳），出现面色发红、眼睛充血、口舌生疮溃烂、手足躁动不安、言语错乱等症状，看起来似乎像是阳证。这就像严冬时节肃杀寒冷，水泽结成坚冰，坚硬是阳刚之象的表现。
邪热未解，属于真阳证，阳气盛极，往往会导致发厥（热厥），厥逆时口鼻没有气息，手脚逆冷，看起来似乎像是阴证。这就像盛夏酷热灼人，树木流淌汁液，汁液是阴柔之象的表现。
所以前人曾说：实证见到虚弱的表象，虚证得到亢盛的假象，错误在于误用补法或泻法；阴证似阳，阳证似阴，错误在于误用温药或凉药。能不仔细辨别吗？
其实这也很容易明白。例如真寒证，表现为四肢厥冷、呕吐、腹痛、泄泻、小便清长频数，即使有发热，也一定想要穿衣盖被，脉象沉小或迟而濡软，眼睛遇到热气症状会稍缓解；真热证，表现为烦躁气喘口渴，声音壮厉，大便秘结，小便赤涩，发热掀开衣被，脉象滑数或大而有力，眼睛疼痛畏光怕热；假寒证，身体虽然冷却厌恶穿衣盖被，大便热且难解，心烦喜欢饮水，上下呼出的气臭秽，脉象迟而有力或沉而鼓激有力；假热证，虽然面红身炽热，但不撤去衣被且神志安静，言语虽然谵妄但气息微弱，或者虚狂起倒，制止就能停止，或者皮肤出现蚊迹花斑且淡红细碎，或者喜欢喝冷水但饮用量不多，或者大便不解但小便多通利，脉象虽然数但濡软，或者浮大无根及芤弦断续；真虚证，面色惨淡形体疲惫，精气衰竭气怯，自汗不止，二便失禁，脉象弱而无神；真实证，内部脏腑结滞，外部经络闭塞，气机壅塞不行，血液留滞成为祸害，脉象形态都盛大；假虚证，外表看似虚弱但脉象病态且争强有力；假实证，病情虽然亢盛但正气已经大衰。
治疗真虚证用补法，治疗真实证用攻法，治疗真寒证用温法，治疗真热证用凉法，这叫做正治与逆治。治疗假寒证要清其内热，内热清除则浮游的阴寒退避。治疗假热证要温其真阳，中焦温暖则虚火归元。治疗假虚证因为正气已损，应当直接去除邪气，邪气去除则身体安宁。治疗假实证因为邪气虽盛，应当兼以补益正气，正气存留则不致发生大患。
而且补法中自有攻邪之意，世上没有正气恢复而邪气不退的情况，也没有正气竭尽而生命不倾覆的情况，万不得已时，也应该从轻从缓，寓攻战于防守之中。这样就可以了，这叫做反治与从治。
总之，能够胜任攻伐治疗的固然是实证，实证多属热，药物虽然是寒性的也不必担忧。不能胜任攻伐治疗的便是虚证，虚证多属寒，药物如果不是温热性质恐怕呼吸之间病情变化，转应不及。因此对于疑似的症状，神色不足以作为凭据，应当参考脉理。脉理又不足以凭据时，应当观察患者的禀赋体质，喜温还是喜凉以及痰、汗、大便、小便的情况，恶寒还是恶热以及病程的新久，用药是否失误，然后施用汤剂，即使不中肯，也不会相差太远。
至于塞因塞用（以补开塞）、通因通用（以通治通）、热因热用（以热治热）、寒因寒用（以寒治寒）、用热远热（热天慎用热药）、用寒远寒（寒天慎用寒药）等方法，例如脾虚导致胀满，用参、术治疗，脾脏得到补益而胀满自然消除。肾虚导致气逆上行，用五味子治疗，肾脏得到补益而气归元海，逆满自然平息。这是塞因塞用。伤寒挟热下利，或者中有燥屎，用调胃承气汤攻下才安稳。痢疾不利，用芍药汤通利而痊愈。这是通因通用。药物本是寒性的，却反佐以热性药；药物本是热性的，却反佐以寒性药，使无拒格（排斥）的隐患，经书所说必须先针对其主要病因而潜伏其病因，开始不同，最终相同，这是热因热用、寒因寒用。寒病适宜投用热药，热病适宜投用寒药，只要中病即可，不要过用，过用反而恐怕被药物所伤，经书所说久而增气，是物化的常理，气增日久，是夭折的原因。这是用热远热、用寒远寒。以上诸法，也是从治的大概原则，扩充充实它，只在于明智良医触类旁通罢了。所以说疾病没有固定的形态，医生没有固定的方剂，药物没有固定的品级，顺应与逆施、进退取决于时机，君臣佐使的运用取决于具体用法，圣神工巧取决于医者本人。那些自用自专以正逆邪（指机械地对待正逆真假）的人，恰好遇到真正的病症时不至于大谬。一旦面对疑似的病症，治疗应当反从，若涉足大海，不知渡口边际，在细微之间，生死凛然。况且假虚的病不多见，而假实的症常有，假寒的错误容易理解，而假热的错误不可救药，一剂药入口，五脏迸裂。人不是木头石头，言语也令人心寒。然而又有反从而逆正，将假病医治成真病的，都是疑似之害造成的。白头穷尽经典，不免一失，可悲啊！所以谨慎编纂这些辨病治病中最难的部分，以告知后人，以仁为己任的人，应当必引为同心。
The difficulty in distinguishing diseases lies not in identifying true conditions, but in differentiating between similar (suspected) conditions. The difficulty in treating diseases lies not in handling direct (Zheng) and reverse (Ni) patterns, but in responding to "reverse treatment" (Fan Zhi) and "following treatment" (Cong Zhi).
When pathogenic factors accumulate within, it is an Excess condition. In severe cases, it may present with silence, reluctance to speak, unwillingness to move the limbs, dizziness, blurred vision, or frequent diarrhea. These are all signs of a great Excess presenting with Deficient appearances. This is like overeating, which leads to fatigue and a desire to lie down.
When the Spleen and Stomach are damaged, it is a Deficiency condition. In severe cases, it may present with abdominal distension and fullness, inability to ingest food, stagnation of Qi, and obstruction of bowel and bladder movements. These are all signs of extreme Deficiency presenting with Excessive appearances. This is like prolonged hunger, which leads to a loss of appetite.
Spleen-Stomach Deficiency-Cold is a True Yin pattern. When Yin Cold reaches its extreme, it often causes "Yin repelling Yang" (Ge Yang), manifesting as red face, red eyes, mouth and tongue ulcers, restless tossing of hands and feet, and confused speech, which superficially resembles a Yang pattern. This is like the severe cold of winter where water freezes into hard ice; hardness is an image of Yang-Gang.
Unresolved pathogenic heat is a True Yang pattern. When Yang Heat reaches its extreme, it often causes Jue (syncope/cold extremities due to heat blockage). During Jue, there is no breath at the mouth and nose, and the hands and feet are cold, which superficially resembles a Yin pattern. This is like the scorching heat of midsummer where trees weep sap; sap is an image of Yin-Soft.
Therefore, predecessors said: When Excess presents with Deficient appearances, and Deficiency presents with Excessive appearances, error lies in mistaken tonification or purgation. When Yin patterns resemble Yang, and Yang patterns resemble Yin, error lies in mistaken warming or cooling. Can one fail to distinguish them?
In fact, this is easy to understand. For example, True Cold manifests as cold extremities, vomiting, abdominal pain, diarrhea, clear and frequent urination. Even if fever occurs, the patient desires clothing. The pulse is deep, small, slow, or soggy; eye discomfort improves with warmth. True Heat manifests as restlessness, panting, thirst, loud voice, constipation, dark and scanty urine, fever with a desire to throw off covers. The pulse is slippery, rapid, large, or forceful; eyes hurt and fear light and heat. False Cold manifests as a cool body but aversion to clothing, hot and difficult stool, irritability, desire for drinks, foul-smelling exhaled air. The pulse is slow but forceful, or deep and surging. False Heat manifests as a red face and hot body, but without removing covers and with calm spirit; speech may be delirious but breath is faint; or false mania with sudden rising and falling that stops when restrained; or skin spots like mosquito bites, pale red and fine; or preference for cold water but drinking little; or constipation with frequent urination. The pulse may be rapid but soggy, or floating, large, rootless, knotted, wiry, or intermittent. True Deficiency manifests as pale complexion, exhausted form, depleted essence, timid Qi, spontaneous sweating, incontinence of bowels and bladder, weak and spiritless pulse. True Excess manifests as internal organ knotting, external meridian closure, Qi stagnation, blood stasis causing harm, and pulses that are all robust. False Deficiency appears emaciated but the pulse is pathological and strong. False Excess appears vigorous but the healthy Qi is greatly depleted.
Treating True Deficiency requires tonification; Treating True Excess requires attack/purgation; Treating True Cold requires warming; Treating True Heat requires cooling. This is called Direct (Zheng) and Reverse (Ni) treatment. Treating False Cold requires clearing internal heat; once internal heat is cleared, floating Yin retreats. Treating False Heat requires warming True Yang; once the middle warms, deficient fire returns to its source. Treating False Deficiency, since healthy Qi is damaged, one should directly eliminate the pathogen; once the pathogen is gone, the body is safe. Treating False Excess, although pathogens are abundant, one should simultaneously tonify healthy Qi; once healthy Qi is preserved, major disaster is avoided.
Moreover, tonification inherently contains the intent to purge. There is no case where healthy Qi recovers while pathogens remain, nor where healthy Qi exhausts while life is preserved. If absolutely necessary, one should proceed lightly and slowly, embedding attack within defense. This is called Reverse (Fan) and Following (Cong) treatment.
In summary, those who can withstand attack therapies are indeed Excess patterns. Excess patterns are mostly Heat; even if drugs are cold, there is no worry. Those who cannot withstand attack therapies are Deficiency patterns. Deficiency patterns are mostly Cold; if drugs are not warm/hot, changes may occur rapidly during breathing, making response too late. Therefore, for suspected symptoms, facial expression and spirit are insufficient evidence; one must refer to pulse theory. If pulse theory is also insufficient, one must observe constitution, preference for warm/cool, phlegm, sweat, stool, urine, aversion to cold/heat, duration of disease, and whether previous medication was erroneous. Then administer decoctions. Even if not perfectly accurate, it will not be far off.
Regarding methods such as "Tonifying to treat obstruction" (Se Yin Se Yong), "Purging to treat discharge" (Tong Yin Tong Yong), "Warming to treat heat" (Re Yin Re Yong), "Cooling to treat cold" (Han Yin Han Yong), "Using heat avoiding heat seasons" (Yong Re Yuan Re), and "Using cold avoiding cold seasons" (Yong Han Yuan Han): For instance, Spleen Deficiency causing distension is treated with Ginseng (Renshen) and Atractylodes (Baizhu); the Spleen is tonified and distension消 (disappears). Kidney Deficiency causing rebellious Qi is treated with Schisandra (Wuweizi); the Kidney is tonified and Qi returns to the source, rebellious fullness calms. This is Tonifying to treat obstruction. Typhoid with heat-induced diarrhea, or dry feces inside, is treated with Tiao Wei Cheng Qi Tang to purge and bring peace. Dysentery with obstruction is treated with Shaoyao Tang to promote flow and cure. This is Purging to treat discharge. Drugs that are inherently cold are counter-assisted with hot drugs; drugs that are inherently hot are counter-assisted with cold drugs, to avoid rejection. As the Classic says: One must first address the primary cause and subdue the underlying reason; they differ at the start but converge at the end. This is Warming to treat heat, Cooling to treat cold. Cold diseases suit hot drugs; heat diseases suit cold drugs. Use only enough to hit the target; do not overuse, lest drug damage occur. As the Classic states: Long-term use increases Qi energy, which is the norm of transformation. Increased Qi over time leads to premature death. This is Using heat avoiding heat seasons, Using cold avoiding cold seasons. The above methods are general principles of Following Treatment. Expanding upon them depends on the wise physician's ability to infer by analogy. Thus it is said: Diseases have no fixed shape; physicians have no fixed formulas; drugs have no fixed categories. Compliance, opposition, advance, and retreat depend on timing. Sovereign, minister, assistant, and courier roles depend on application. Sage-like skill depends on the person. Those who rigidly apply standard opposites to true/reverse patterns may not err greatly when facing true diseases. But once facing suspected diseases, where treatment requires reverse/following approaches, it is like crossing a vast sea without knowing the shore. Between subtle nuances, life and death hang in the balance. Moreover, False Deficiency is rare, while False Excess is common. Errors in False Cold are understandable, but errors in False Heat are incurable; one dose enters, and the five viscera burst. Humans are not wood or stone; such words chill the heart. Yet there are cases where following treatment opposes the truth, turning false illness into true illness. All these harms stem from suspicion/similarity. White-haired scholars exhausting classics still make mistakes. How sad! Therefore, I carefully compile these most difficult aspects of distinguishing and treating diseases to inform future generations. Those who take benevolence as their responsibility should surely share this sentiment.