凡病俱以虚实寒热四字为大纲，温热症何独不然？但虚实寒热之真者易辨，似者难辨。有实症似虚，虚症似实，热
症似寒，寒症似热者，不可不细辨也，故特逐论而详述之。
所谓实症似虚者，即以表症论之，头痛发热，邪在表也。其脉当浮，症当无汗，而反自汗，脉无力，用发表药，而
身反疼痛，则似虚矣。故人惑于多自汗，而误用桂枝汤者有之；惑于脉无力，而引仲景《太阳篇》发热恶寒脉微弱为无
阳，而误用小建中汤者有之；惑于身疼痛，而引仲景若不瘥，身体疼痛，当温其里，误用四逆汤者有之。不知伏邪之在
表，其自汗者，邪热自里蒸出于表，非表虚也；其脉无力者，热主散漫，散漫则脉软，非比寒主收敛而脉紧也；身体反
疼者，伏邪自里而渐出于表，非比阳虚不任发表也。此在表之实症似虚者也。
又以半表半里论之，寒热往来，胸胁满，邪在半表半里也。其脉当弦，其口当渴，而脉反沉，口不渴，则似寒矣。
故人惑于脉沉，而以胸胁满为太阴，口不渴为内寒，而误用理中汤，不知伏邪之半表半里，其脉沉者，邪伏于膜原而未
出表，故脉不浮，非阳虚也。其不渴者，邪未传变，未入胃腑，故不能消水，非内寒也。此半表半里之热症似寒者也。
又以里症论之口燥咽干不得卧，邪在里。其脉当洪，其身当热，其盒饭结，而脉反沉微涩弱，身反四肢厥冷，大便自利，
则全似虚寒矣。人惑于脉微涩弱，而用参 者有之；惑于厥逆，而用桂附者有之；惑于自利，而用参、术、干姜者有之。
不知伏邪在里，其脉沉微涩弱者，乃邪热结于肠胃，气不达于营卫也；其身反厥冷者，邪热结于里，而不达于外，气结
于下，而不通于上也；其自利者，乃热结旁流也。此在里之实症似虚、热症似寒者也。
总之，温热为伏火，与风寒之寒因大异。故脉症虽有似虚似寒之时，而一一辨其为温热症，则属邪盛而反见虚寒之
假象，明眼人不当为其所惑也。
所谓虚症似实者，即以表症论之，头痛、发热、身疼痛、自汗、脉浮大，邪在表也。而屡用清凉表散，其症不减者，
非药力之不专，乃正气不能使药力达表，阴液不能随阳气作汗也。此伏邪在表时，虚症之似实者也。气虚者，加参 于
表药中即汗；阴虚者，加润剂于表药中即汗。若不知其气血之两亏，而宣表不已，势必暴厥而脱。
更以半表半里论之，胸胁满、耳聋、呕吐、如疟状、脉弦，邪在半表半里也。而屡用和解消导，其症更加者，非药
力之不到，乃中焦脾胃伤而气不运，肝阴伤而火更燥也。此伏邪在半表半里时，虚症之似实者也。必合四君、六君（人
参、白术、茯苓、甘草、姜、枣，为四君子汤，加陈皮、半夏，名六君子汤）于和解药中，合四物（当归、生地、芍药、
川芎）于清解药中，始能战汗而解。若更消导清解不已，必至胃气绝而死。
更以里症论之，舌苔黄黑裂燥芒刺、胸腹胁脐硬痛，大小便闭、六脉数大，邪在里也。而屡用攻利药，或总不得利，
或利后愈甚，乃正气不能传送肠胃，血液不能滋润肠胃，非药力之不峻也。此伏邪传里时，虚症之似实者也。气虚者，
助胃以资传送；血枯者，养阴以藉濡滑。气行津化，方得通利。若不知其亏竭，而恣意攻利，必昏沉痿顿而死。
总之，药不中病，则伤正气。伤其下，则正气浮越而上逆；伤其中，则正气虚散而外越。脉症虽有似实似热之时，
而一询其来路，若已治之太过，则属气从内夺，正气夺则虚，明眼人当不为其所惑也。
夫一症而虚实互异，用药稍误而生死攸分，将以何者为辨症之把柄乎？曰∶以下列五辨法辨之，则了然矣。而更以
曾经误治、与未经误治，辨其伏邪之为实为虚，为实中夹虚，为虚中夹实，则得其大纲，而更得其细目，然后似是而非
之症，断不能惑矣。余于各论条下，每症细辨其虚实，而此先详言以通论之者，则以散见诸条，尚恐忽略，故首先总论
其吃紧处也。至若寒极似热，则惟伤寒诸症有之，而为温热症之所绝无，故不论及。
凡疾病都以“虚、实、寒、热”四个字作为总纲，温热病（由温热邪气引起的疾病）难道会例外吗？但是，真正的虚、实、寒、热容易辨别，而似是而非的则难以辨别。有实证表现为虚象，虚证表现为实象，热证表现为寒象，寒证表现为热象的情况，不能不仔细辨别，因此特意逐一论述并详细说明。
所谓“实证似虚”，就以表证（病邪在肌表）来说，头痛发热，说明邪气在表。脉象应当浮，症状应当无汗，却反而自汗出，脉象无力，使用发汗解表的药物后，身体反而疼痛，这就看似虚证了。所以有人被多汗迷惑，误用桂枝汤（调和营卫的方剂）；有人被脉无力迷惑，引用张仲景《伤寒论·太阳篇》中“发热恶寒脉微弱为无阳”的说法，误用小建中汤（温中补虚的方剂）；有人被身体疼痛迷惑，引用张仲景所说“如果不愈，身体疼痛，应当温里”，误用四逆汤（回阳救逆的方剂）。他们不知道伏邪（潜伏体内的邪气）在表时，其自汗是因为邪热从体内蒸腾到体表，并非表虚；其脉无力是因为热邪主散漫，散漫则脉象软弱，不像寒邪主收敛而导致脉紧；身体反而疼痛，是因为伏邪从体内逐渐透出体表，不像阳虚不能耐受发汗药一样。这就是在表的实证表现为虚象。
再从半表半里（病位介于表里之间）来说，寒热往来（忽冷忽热），胸胁胀满，说明邪气在半表半里。脉象应当弦，口应当渴，却反而脉沉，口不渴，这就看似寒证了。所以有人被脉沉迷惑，认为胸胁满是太阴病，口不渴是内寒，从而误用理中汤（温中祛寒的方剂）。他们不知道伏邪在半表半里时，脉沉是因为邪气伏于膜原（半表半里的深层部位）而未透出体表，所以脉不浮，并非阳虚；口不渴是因为邪气尚未传变，未进入胃腑，所以不能消耗津液导致口渴，并非内寒。这就是半表半里的热证表现为寒象。
再从里证（病邪在脏腑内部）来说，口燥咽干无法安卧，说明邪气在里。脉象应当洪大，身体应当发热，大便应当结硬，却反而脉沉微涩弱，身体反而四肢厥冷，大便自利（腹泻），这就完全像虚寒证了。有人被脉微涩弱迷惑，使用人参等补气药；有人被四肢厥逆迷惑，使用肉桂、附子等温热药；有人被自利迷惑，使用人参、白术、干姜等温补药。他们不知道伏邪在里时，脉沉微涩弱是因为邪热结聚在肠胃，气机不能通达营卫；身体反而厥冷，是因为邪热结聚在里，不能通达于外，气结于下，不能通于上；其自利，乃是热结旁流（实热内结，迫津下泄导致的腹泻）。这就是在里的实证表现为虚象、热证表现为寒象。
总之，温热病属于伏火，与风寒病的寒因大不相同。所以虽然脉症有时看似虚寒，但一一辨别其为温热病，则属于邪气盛实而反见虚寒的假象，明眼人不会被其所迷惑。
所谓“虚证似实”，就以表证来说，头痛、发热、身体疼痛、自汗、脉浮大，这是邪气在表。但如果多次使用清凉解表的药物，症状不减，这不是药力不专一，而是正气不能使药力到达体表，阴液不能随着阳气化作汗液。这是伏邪在表时，虚证表现为实象。气虚的人，在解表药中加入人参就会出汗；阴虚的人，在解表药中加入滋润药就会出汗。如果不知道气血两亏，而一味宣散发表，势必会导致暴厥而脱证。
再从半表半里来说，胸胁胀满、耳聋、呕吐、像疟疾一样的症状、脉弦，这是邪气在半表半里。但如果多次使用和解消导的药物，症状反而加重，这不是药力不到，而是中焦脾胃受伤而气机不运，肝阴受伤而火势更燥。这是伏邪在半表半里时，虚证表现为实象。必须将四君子汤（人参、白术、茯苓、甘草，加生姜、大枣）、六君子汤（四君子汤加陈皮、半夏）合入和解药中，将四物汤（当归、生地、芍药、川芎）合入清解药中，才能通过战汗（先寒战后汗出）而痊愈。如果继续一味消导清解，必然导致胃气绝而死。
再从里证来说，舌苔黄黑裂燥且有芒刺、胸腹胁脐硬痛，大小便闭塞、六脉数大，这是邪气在里。但如果多次使用攻下利下的药物，要么始终不得利，要么利后症状更重，这是正气不能传送肠胃，血液不能滋润肠胃，不是药力不够峻猛。这是伏邪传入里时，虚证表现为实象。气虚者，助胃气以资助传送；血枯者，养阴液以借助濡滑。气行津化，才能通利。如果不知道其亏竭，而肆意攻下利下，必然导致昏沉痿顿而死。
总之，药不对症，就会损伤正气。伤及其下部，则正气浮越而上逆；伤及其中部，则正气虚散而外越。脉症虽然有时看似实热，但只要询问其治疗经过，如果发现已经治疗太过，则属于元气从内部被剥夺，正气被夺则虚，明眼人不会被其所迷惑。
同一个症状，虚实互异，用药稍有误判就关乎生死，将以什么作为辨证的把柄呢？回答说：用下面五种辨证方法来辨别，就能清楚了。再结合曾经误治和未经误治的情况，来辨别伏邪是实证、是虚证、是实中夹虚、还是虚中夹实，这样既掌握了大纲，又得到了细目，然后那些似是而非的症状，绝对不能迷惑人了。我在各条论述下，对每个症状都仔细辨别虚实，而这里先详细言说以作通论，是因为散见于各条的内容，恐怕会被忽略，所以首先总论其关键之处。至于寒极似热，只有伤寒诸症有之，而温热病绝无此情况，故不予讨论。
All diseases take "deficiency, excess, cold, and heat" as the general principles. How could warm-heat diseases (diseases caused by warm-heat pathogens) be an exception? However, true deficiency, excess, cold, and heat are easy to differentiate, while those that appear similar but are different are difficult to identify. There are cases where excess syndromes resemble deficiency, deficiency syndromes resemble excess, heat syndromes resemble cold, and cold syndromes resemble heat; these must not fail to be carefully differentiated. Therefore, I specifically discuss them one by one in detail.
The so-called "excess syndrome resembling deficiency," taking exterior syndromes (pathogens located on the body surface) as an example: headache and fever indicate the pathogen is in the exterior. The pulse should be floating (superficial), and symptoms should include absence of sweating. Yet, spontaneous sweating occurs instead, the pulse is forceless, and after using diaphoretic (sweat-inducing) herbs, the body pain反而 worsens. This appears like a deficiency syndrome. Thus, some people, confused by excessive spontaneous sweating, mistakenly use Guizhi Tang (Cinnamon Twig Decoction); some, confused by the forceless pulse, cite Zhang Zhongjing's *Treatise on Cold Damage* (Shanghan Lun), Chapter on Taiyang Disease, stating "fever, aversion to cold, and weak pulse indicate lack of Yang," and mistakenly use Xiaojianzhong Tang (Minor Construct the Middle Decoction); some, confused by body pain, cite Zhang Zhongjing's saying "if not resolved, with body pain, one should warm the interior," and mistakenly use Sini Tang (Frigid Extremities Decoction). They do not know that when latent pathogens (pathogens lying dormant within the body) are in the exterior, spontaneous sweating is due to pathogenic heat steaming from the interior to the exterior, not exterior deficiency; the forceless pulse is because heat pathogens tend to scatter, making the pulse soft, unlike cold pathogens which tend to contract, causing a tight pulse; body pain occurs because latent pathogens gradually emerge from the interior to the exterior, unlike Yang deficiency which cannot tolerate diaphoresis. This is the case of exterior excess syndromes resembling deficiency.
Taking half-exterior half-interior (pathogen location between the exterior and interior) as an example: alternating chills and fever, and fullness in the chest and hypochondrium indicate the pathogen is in the half-exterior half-interior. The pulse should wiry, and there should be thirst. Yet, the pulse is deep, and there is no thirst, appearing like a cold syndrome. Thus, some people, confused by the deep pulse, consider chest and hypochondriac fullness as a Taiyin disease and no thirst as internal cold, mistakenly using Lizhong Tang (Regulate the Middle Decoction). They do not know that when latent pathogens are in the half-exterior half-interior, a deep pulse indicates the pathogen is lodged in the Membrane Source (a specific location between the interior and exterior) and has not yet emerged to the exterior, hence the pulse is not floating, not indicating Yang deficiency; no thirst indicates the pathogen has not transformed or transmitted into the Stomach Fu organ, hence it does not consume fluids to cause thirst, not indicating internal cold. This is the case of heat syndromes in the half-exterior half-interior resembling cold.
Taking interior syndromes (pathogens inside the Zang-Fu organs) as an example: dry mouth and throat, inability to lie down indicate the pathogen is in the interior. The pulse should be surging, the body hot, and stool constipated. Yet, the pulse is deep, fine, choppy, and weak; the body has cold extremities; and there is spontaneous diarrhea. This completely resembles a deficiency-cold syndrome. Some people, confused by the fine, choppy, and weak pulse, use Renshen (Ginseng Radix et Rhizoma); some, confused by cold extremities, use Rougui (Cortex Cinnamomi) and Fuzi (Radix Aconiti Lateralis Preparata); some, confused by spontaneous diarrhea, use Renshen, Baizhu (Atractylodis Macrocephalae Rhizoma), and Ganjiang (Zingiberis Rhizoma). They do not know that when latent pathogens are in the interior, a deep, fine, choppy, and weak pulse is due to pathogenic heat knotting in the intestines and stomach, preventing Qi from reaching Ying and Wei (nutritive and defensive levels); cold extremities occur because pathogenic heat knots in the interior and cannot reach the exterior, with Qi knotted below and unable to communicate above; spontaneous diarrhea is actually "diarrhea surrounding a fecal impaction" (heat knotting internally forcing fluid out). This is the case of interior excess syndromes resembling deficiency and heat syndromes resembling cold.
In summary, warm-heat diseases belong to latent fire, greatly differing from the cold causes of wind-cold diseases. Although pulses and symptoms may sometimes resemble deficiency and cold, once differentiated as warm-heat diseases, they belong to excess pathogens presenting false signs of deficiency and cold. Clear-sighted practitioners will not be misled.
The so-called "deficiency syndrome resembling excess," taking exterior syndromes as an example: headache, fever, body pain, spontaneous sweating, and a large floating pulse indicate the pathogen is in the exterior. If cooling and dispersing herbs are used repeatedly without symptom reduction, it is not due to lack of efficacy, but because Zhengqi (healthy Qi) cannot drive the medicinal power to the exterior, and Yin fluids cannot transform into sweat following Yang Qi. This is the case of exterior deficiency syndromes resembling excess when latent pathogens are present. For Qi deficiency, adding Renshen (Ginseng Radix et Rhizoma) to exterior-dispersing herbs induces sweating; for Yin deficiency, adding moistening herbs to exterior-dispersing herbs induces sweating. If one fails to recognize the dual deficiency of Qi and Blood and continues to disperse the exterior excessively, sudden collapse and syncope will inevitably occur.
Taking the half-exterior half-interior as an example: chest and hypochondriac fullness, deafness, vomiting, malaria-like symptoms, and a wiry pulse indicate the pathogen is in the half-exterior half-interior. If harmonizing and guiding-out herbs are used repeatedly with worsening symptoms, it is not due to ineffective medication, but because the Middle Jiao (Spleen and Stomach) is injured with stagnant Qi transport, and Liver Yin is injured with intensified Fire dryness. This is the case of half-exterior half-interior deficiency syndromes resembling excess when latent pathogens are present. One must combine Sijunzi Tang (Four Gentlemen Decoction: Renshen, Baizhu, Fuling (Poria), Gancao (Licorice Root), plus Shengjiang (Fresh Ginger) and Dazao (Jujube)), Liujunzi Tang (Six Gentlemen Decoction: Sijunzi Tang plus Chenpi (Tangerine Peel) and Banxia (Pinellia Tuber)) with harmonizing herbs, and Siwu Tang (Four Substance Decoction: Danggui (Angelica Sinensis Radix), Shengdi Huang (Rehmanniae Radix Preparata), Shaoyao (Paeoniae Radix), Chuanxiong (Ligustici Chuanxiong Rhizoma)) with clearing and resolving herbs, to achieve resolution through battle-sweat (shivering followed by sweating). If one continues to use guiding-out and clearing-resolving methods excessively, gastric Qi will perish, leading to death.
Taking interior syndromes as an example: yellow or black, cracked, dry tongue coating with prickles; hardness and pain in the chest, abdomen, hypochondrium, and umbilicus; obstruction of urination and defecation; and rapid, large pulses in all six positions indicate the pathogen is in the interior. If purgative and draining herbs are used repeatedly, either failing to produce evacuation or worsening symptoms after evacuation, it is because Zhengqi cannot transport waste in the intestines and stomach, and Blood cannot moisten the intestines and stomach; this is not due to insufficient potency of the drugs. This is the case of interior deficiency syndromes resembling excess when latent pathogens have transmitted inward. For Qi deficiency, assist Stomach Qi to aid transport; for Blood dryness, nourish Yin to facilitate lubrication. Only when Qi moves and fluids transform can there be free passage. If one ignores the depletion and indulges in aggressive purging, coma, flaccidity, and exhaustion will lead to death.
In summary, if medicine does not target the disease, it damages Zhengqi. Damage to the lower part causes Zhengqi to float upward and rebel; damage to the middle part causes Zhengqi to scatter outward. Although pulses and symptoms may sometimes resemble excess and heat, if one inquires into the treatment history and finds excessive treatment has occurred, it belongs to Yuanqi (Primordial Qi) being deprived from within. When Zhengqi is deprived, it becomes deficiency. Clear-sighted practitioners will not be misled.
For the same symptom, deficiency and excess differ; a slight error in medication determines life or death. What should be the handle for differentiation? I answer: Use the following five differentiation methods to clarify. Furthermore, by distinguishing between previously mis-treated and untreated cases, determine whether the latent pathogen is excess, deficiency, excess with deficiency admixed, or deficiency with excess admixed. Grasping both the general outline and detailed aspects ensures that ambiguous symptoms cannot confuse the practitioner. In my discussions under each item, I carefully differentiate deficiency and excess for every symptom. Here, I provide a general discussion first because scattered points in various sections might be overlooked; thus, I summarize the critical points at the beginning. As for "extreme cold resembling heat," this only occurs in various cold-damage syndromes and is absolutely absent in warm-heat diseases, so it is not discussed here.