寒热有真假者，阴证似阳，阳证似阴也。盖阴极反能躁热，乃内寒而外热，即真寒假热
也。阳极反能寒厥，乃内热而外寒，即真热假寒也。假热者，最忌寒凉，假寒者，最忌温热
。察此之法，当专以脉之虚实强弱为主。
一、假热者，水极似火也。凡病伤寒，或患杂证，有其素禀虚寒，偶感邪气而然者，有
过于劳倦而致者，有过于酒色而致者，有过于七情而致者，有原非火证，以误服寒凉而致者
。凡真热本发热，而假热亦发热。其证则亦为面赤躁烦，亦为大便不通，小便赤涩，或为气
促，咽喉肿痛，或为发热，脉见紧数等证。昧者见之，便认为热，妄投寒凉，下咽必毙。不
知身虽有热，而里寒格阳，或虚阳不敛者，多有此证。但其内证，则口虽干渴，必不喜冷，
即喜冷者，饮亦不多，或大便不实，或先硬后溏，或小水清频，或阴枯黄赤，或气短懒
言，或色黯神倦，或起倒如狂，而禁之则止，自与登高骂詈者不同，此虚狂也；或斑如蚊迹
而浅红细碎，自与紫赤热极者不同，此假斑也。凡假热之脉，必沉细迟弱，或虽浮大紧数而
无力无神，此乃热在皮肤，寒在脏腑，所谓恶热非热，实阴证也。凡见此内颓内困等证，而
但知攻邪，则无有不死。急当以四逆、八味、理阴煎、回阳饮之类，倍加附子填补真阳，以
引火归源，但使元气渐复，则热必退藏，而病自愈。所谓火就燥者，即此义也。故凡见身热
脉数，按之不鼓击者，此皆阴盛格阳，即非热也。仲景治少阴证面赤者，以四逆汤加葱白主
之。东垣曰∶面赤目赤，烦躁引饮，脉七八至，按之则散者，此无根之火也。以姜附汤加人
参主之。《外台秘要》曰∶阴盛发躁，名曰阴躁，欲坐井中，宜以热药治之。
一、假寒者，火极似水也。凡伤寒热甚，失于汗下，以致阳邪亢极，郁伏于内，则邪自
阳经传入阴分，故为身热发厥，神气昏沉，或时畏寒，状若阴证。凡真寒本畏寒，而假寒亦
畏寒，此热深厥亦深，热极反兼寒化也。大抵此证，必声壮气粗，形强有力，或唇焦舌黑，
口渴饮冷，小便赤涩，大便秘结，或因多饮药水，以致下痢纯清水，而其中仍有燥粪，及矢
气极臭者，察其六脉必皆沉滑有力，此阳证也。凡内实者，宜三承气汤择而用之。潮热者，
以大柴胡汤解而下之。内不实者，以白虎汤之类清之。若杂证之假寒者，亦或为畏寒，或为
战栗，此以热极于内而寒侵于外，则寒热之气两不相投，因而寒栗，此皆寒在皮肤，热在骨
髓，所谓恶寒非寒，明是热证。但察其内证，则或为喜冷，或为便结，或小水之热涩，或口
臭而躁烦，察其脉必滑实有力。凡见此证，即当以凉膈、芩连之属，助其阴而清其火，使内
热既除，则外寒自伏。所谓水流湿者，亦此义也。故凡身寒厥冷，其脉滑数，按之鼓击于指
下者。此阳极似阴，即非寒也。
一、假寒误服热药，假热误服寒药等证，但以冷水少试之。假热者，必不喜水，即有喜
者，或服后见呕，盒饭以温热药解之。假寒者，必多喜水，或服后反快而无所逆者，盒饭以
寒凉药解之。
寒热有真假之分，即阴证表现出阳证的假象，阳证表现出阴证的假象。当阴寒至极时，反而会出现躁动发热的症状，这是内部寒冷而外部发热，也就是真寒假热。当阳热至极时，反而会出现四肢厥冷的症状，这是内部炎热而外部寒冷，也就是真热假寒。对于假热证，最忌讳使用寒凉药物；对于假寒证，最忌讳使用温热药物。辨别这种真假的方法，应当专门以脉象的虚实强弱作为主要依据。
一、假热证，是水气极盛而似火的表现。凡是患伤寒病，或患有其他杂病，有的是因为素体禀赋虚寒，偶然感受邪气所致；有的是因为过度劳累所致；有的是因为过度饮酒色欲所致；有的是因为过度情志刺激所致；有的原本不是火证，而是因为误服寒凉药物所致。凡是真热证本来就会发热，而假热证也会发热。其症状表现为面色潮红、烦躁不安，大便不通，小便赤涩，或者气促，咽喉肿痛，或者发热，脉象紧数等。愚昧的医生见到这些症状，便认为是热证，妄用寒凉药物，药液咽下后必然导致死亡。他们不知道身体虽然有热，但这是因为里寒格拒阳气，或者是虚阳不能收敛，所以多有此证。但是观察其内部的证候，虽然口干燥渴，一定不喜欢冷饮，即使喜欢冷饮，喝得也不多；或者大便不成形，或者先干后稀；或者小便清长频数；或者阴部干枯发黄；或者气短懒言；或者面色晦暗、精神疲倦；或者起倒如狂，但制止后就能停止，这与登高骂人的实证狂乱不同，这是虚性狂乱；或者出现斑疹像蚊子叮咬的痕迹，颜色浅红细碎，这与紫红色热极的斑疹不同，这是假斑。凡是假热证的脉象，必定沉细迟弱，或者虽然浮大紧数但无力无神，这是热在皮肤，寒在脏腑，所说的恶热并非真热，实际上是阴证。凡是见到这种内部颓败困顿的症状，如果只知道攻伐邪气，就没有不死亡的。应当紧急使用四逆汤、八味丸、理阴煎、回阳饮等方剂，加倍加入附子来填补真阳，以引导火气回归本源，只要使元气逐渐恢复，那么热势必然退藏，疾病自然痊愈。所谓“火就燥”，就是这个道理。所以凡是见到身体发热、脉象数急，但按压时不鼓击有力的，这都是阴盛格阳，并不是热证。张仲景治疗少阴证出现面赤的，用四逆汤加葱白为主方。李东垣说：面赤目赤，烦躁引饮，脉象七八至，按压则散乱的，这是无根之火。用姜附汤加人参为主方。《外台秘要》说：阴盛导致发躁，名叫阴躁，病人想坐在井中，应当用热药治疗。
二、假寒证，是火气极盛而似水的表现。凡是伤寒热势严重，失于发汗或攻下，导致阳邪亢盛至极，郁伏在体内，那么邪气就会从阳经传入阴分，所以出现身体发热但四肢厥冷，神气昏沉，有时畏寒，状若阴证。凡是真寒证本来畏寒，而假寒证也畏寒，这是热邪深入则厥冷也深，热极反而兼有寒化的表现。大体上这种证候，必定声音壮实、气息粗重，形体强壮有力，或者嘴唇焦黑，口渴想喝冷水，小便赤涩，大便秘结；或者因为多喝药水，导致下痢纯清水，但其中仍有燥屎，以及放屁极臭的，检查其六脉必定都沉滑有力，这是阳证。凡是内部实热的，宜选择三承气汤使用。有潮热症状的，用大柴胡汤和解并攻下。内部不实的，用白虎汤之类清热。如果是杂病中的假寒证，也可能表现为畏寒，或者战栗，这是因为热极于内而寒侵于外，寒热之气互不相容，因而产生寒栗，这都是寒在皮肤，热在骨髓，所说的恶寒并非真寒，明明是热证。只要观察其内部证候，或者喜欢冷饮，或者大便秘结，或者小便热涩，或者口臭且烦躁，检查其脉象必定滑实有力。凡是见到这种证候，就应当使用凉膈散、黄芩黄连之类的药物，资助阴液而清除火热，使内部热邪既除，那么外部寒象自然潜伏。所谓“水流湿”，也是这个道理。所以凡是身体寒冷厥冷，但脉象滑数，按压时鼓击于指下的，这是阳极似阴，并不是寒证。
三、假寒证误服热药，假热证误服寒药等情况，可以用少量冷水试之。假热证的人，一定不喜欢水，即使有喜欢的，或者服药后出现呕吐，应当立即用温热药解救。假寒证的人，一定多喜欢水，或者服药后反而舒适而没有不良反应的，应当立即用寒凉药解救。
There are true and false manifestations of cold and heat, namely Yin syndromes resembling Yang, and Yang syndromes resembling Yin. When Yin-cold reaches its extreme, it may paradoxically manifest as restlessness and heat; this is internal cold with external heat, known as True Cold and False Heat. When Yang-heat reaches its extreme, it may paradoxically manifest as cold extremities (Jue); this is internal heat with external cold, known as True Heat and False Cold. For False Heat, the greatest contraindication is the use of Cold-Cooling remedies; for False Cold, the greatest contraindication is the use of Warm-Hot remedies. The method to discern this lies primarily in examining the deficiency or excess, and strength or weakness of the pulse.
I. False Heat is when Water (Cold) is at its extreme and resembles Fire (Heat). In cases of Shanghan (Cold Damage) or other miscellaneous diseases, this may arise from a constitution inherently deficient and cold, accidentally contracting pathogenic factors; from excessive fatigue; from excessive indulgence in alcohol and sexual activity; from excessive emotional stress; or from a condition originally not characterized by Fire, but caused by the mistaken administration of Cold-Cooling drugs. Both True Heat and False Heat present with fever. Symptoms include flushed face, restlessness, constipation, dark and scanty urine, shortness of breath, sore throat, or fever with a tight and rapid pulse. Ignorant physicians seeing these signs assume it is Heat and recklessly administer Cold-Cooling drugs, which will inevitably lead to death upon ingestion. They fail to realize that although the body feels hot, it is due to Internal Cold repelling Yang Qi, or Deficient Yang failing to consolidate. However, observing the internal signs: although the mouth is dry and thirsty, there is no desire for cold drinks; even if desired, intake is small; stool may be loose, or hard initially then soft; urine may be clear and frequent; the genitals may appear dry and yellowish; there may be shortness of breath and reluctance to speak; complexion may be dull with mental fatigue; or there may be manic behavior like rising and falling, which stops when restrained, differing from the shouting and cursing seen in Excess mania (this is Deficient Mania); or macules may appear like mosquito bites, light red and fine, differing from the purple-red macules of extreme Heat (this is False Macules). The pulse in False Heat must be deep, fine, slow, and weak, or if floating, large, tight, and rapid, it lacks force and spirit. This indicates Heat on the skin and Cold in the Zang-Fu organs. This is what is meant by "aversion to heat" not being true Heat, but actually a Yin syndrome. If one sees such internal collapse and distress and only knows how to attack the pathogen, death is certain. One must urgently use formulas such as Sini Tang (Four Reversal Decoction), Bawei Wan (Eight-Ingredient Pill), Liyin Jian (Yin-Regulating Decoction), or Huiyang Yin (Yang-Recovering Drink), doubling the dosage of Fuzi (Aconiti Lateralis Radix Praeparata) to tonify True Yang and guide Fire back to its source. Once Yuan Qi (Original Qi) gradually recovers, the Heat will retreat and subside, and the disease will heal spontaneously. This illustrates the principle that "Fire follows dryness." Therefore, whenever fever and a rapid pulse are present, but pressing reveals no beating force against the fingers, this is Yin Excess repelling Yang, and is not Heat. Zhang Zhongjing treated Shaoyin syndrome presenting with a flushed face using Sini Tang plus Congbai (Allii Tuberosi Bulbus). Li Dongyuan stated: Flushed face and eyes, restlessness with thirst, pulse rate of 7-8 beats per breath, scattering upon pressure, indicates Rootless Fire. Treat with Jiangfu Tang (Ginger and Aconite Decoction) plus Renshen (Ginseng Radix et Rhizoma). The *Waitai Miyao* states: Yin Excess causing restlessness is called Yin Restlessness; the patient desires to sit in a well, and should be treated with Hot medicines.
II. False Cold is when Fire (Heat) is at its extreme and resembles Water (Cold). In severe Shanghan with Heat, if sweating or purging is neglected, Yang Pathogens become hyperactive and stagnant internally. The pathogen then transmits from Yang meridians into Yin levels, resulting in fever with cold extremities, mental lethargy, and occasional aversion to cold, resembling a Yin syndrome. True Cold inherently involves aversion to cold, and False Cold also involves aversion to cold; this is because deeper Heat leads to deeper Jue (cold extremities), and extreme Heat paradoxically manifests with Cold transformations. Generally, this syndrome presents with a strong voice and coarse breathing, robust physical strength, scorched lips and black tongue, thirst with desire for cold drinks, dark and scanty urine, and constipation. Or, due to excessive intake of medicinal fluids, it may cause diarrhea of pure clear water while dry feces remain inside, accompanied by extremely foul-smelling flatus. Examination of the six pulses will reveal them all to be deep, slippery, and forceful, indicating a Yang syndrome. For internal Excess, choose among the Three Chengqi Tangs (Three Miracle Formulas). For tidal fever, use Dachaihu Tang (Major Bupleurum Decoction) to harmonize and purge. For internal non-excess, use Baizhu Tang (White Tiger Decoction) to clear Heat. In miscellaneous diseases presenting as False Cold, there may be aversion to cold or shivering. This occurs because Heat is extreme internally while Cold invades externally, causing the two energies to clash, resulting in chills. This is Cold on the skin and Heat in the marrow. This means "aversion to cold" is not true Cold, but clearly a Heat syndrome. Observing internal signs: desire for cold drinks, constipation, hot and painful urination, bad breath with restlessness. The pulse must be slippery, full, and forceful. Upon seeing this, one should use Lianpo San (Cool the Chest Powder) or Huangqin and Huanglian (Scutellariae Radix and Coptidis Rhizoma) to nourish Yin and clear Fire. Once internal Heat is removed, external Cold will naturally subside. This illustrates the principle that "Water flows to dampness." Therefore, whenever the body is cold and extremities are chilled, but the pulse is slippery and rapid, beating forcefully against the fingers upon pressure, this is Yang Extreme resembling Yin, and is not Cold.
III. For conditions where False Cold is mistakenly treated with Hot medicines, or False Heat with Cold medicines, a small amount of cold water can be used as a test. Patients with False Heat will definitely dislike water; even if they show some preference, vomiting may occur after drinking, requiring immediate relief with Warm-Hot medicines. Patients with False Cold will generally prefer water; if they drink it and feel comfortable without adverse reactions, it should be relieved immediately with Cold-Cooling medicines.