经言∶寒伤形，寒伤皮毛，寒伤血，寒伤荣。然寒主闭藏而腠理闭密，阳气拂郁不能通畅，怫
然内作，故身热燥而无汗。故经曰；人之伤于寒也，则为病热。又曰∶夫热病皆伤寒之类也。《内经》
既直言热病者，言一身为病之热气也；以至仲景直言伤寒者，言外伤之寒邪也，以分风、寒、暑、湿之
所伤，主疗不同，故只言伤寒，而不通言热病也。其寒邪为害至大，故一切内外所伤，俱为受汗之热病者，
通谓之伤寒也。一名大病者，皆以为害之大也。又春曰温病，夏曰热病，秋曰湿病，冬曰伤寒。伤寒者
是随四时天气春温、夏热、秋湿、冬寒为名，以明四时病之微甚，及主疗消息，稍有不等，
大而言之则一也，非为外伤及内病有此异耳。或云冬伏寒邪于肌肤骨肉之间，至于春变为温病，夏变为
热病，秋变为湿病，冬变为正伤寒病者，及名冒其寒而内生拂热，热微而不即病者，以至将来阳热变动，
或又感之而成热病，非谓伏其寒气而反变寒为热也。经曰∶冬伤于寒，春必病温。亦其义也。亦
有一时冒寒而便为热病者，或感四时不正乖戾之气，或随气运兴衰变动，或内外诸邪所伤，或因他病变成，
或因他人传染皆能成之，但以分门随证治之耳。经言此六经传受，乃外伤于寒而为热病之大略，主疗
之要法也。大法曰∶伤寒一日，太阳受之，故头项痛，腰脊强。
此足太阳膀胱之经也，故与经言五日足少阴肾水为其表里。或言为手太阳者，误也。此六经之证
也，或以此直云伤寒不传手经者，亦误也。岂不详热论云五脏六腑皆受病，又刺热篇皆言五脏热病。但
以热病多于足经，而其病甚少于手经，而其病微，且与足经微为兼证，汗下之治，但分表里，故不
单言手经，而但寄于足经而已。若针刺，则本经补泻，各分五脏手足之经矣。
二日阳明受之，故身热、目疼、鼻干，不得眠也。
三日少阳受之，故胸胁痛而耳聋。
四日太阴受之，故腹满而咽干。
五日少阴受之，故目燥、舌干而渴。
六日厥阴受之，则烦满囊缩。
或言传手厥阴包络相火，则水火既济而愈；传足厥阴肝经，则土败木贼
而当死者，妄说也。此经言足厥阴肝经之证也。
大法曰∶前三日三阳病，在表，故宜汗之。
汗泄热退身凉而愈。
后三日三阴病，在里，故宜下之。
下，退里热，则怫热宣通，汗出气和而愈也。亦有内热下尽，无汗气和而愈
者也。或曰前三日寒在表者，误也。此皆热证也。
或未愈者，再经衰之，七日太阳病衰（自此以下皆言病自衰减），头项少愈；八日阳
明病衰，身热少愈；九日少阳病衰，耳能微闻；十日太阴病衰，身热少愈，腹满
如故；十一日少阴病衰，渴止、不满（以言腹不复满），舌干，已而嚏；十二日厥阴病
衰，囊纵、少腹微下，大气皆去（言大病热气散去），病则瘳（音抽，愈也）矣。
此亦大略言之耳，伤寒受不必拘此，但以明其诸证而如法治疗耳。
经文说：寒邪损伤形体，寒邪损伤皮毛，寒邪损伤血分，寒邪损伤营气。然而，寒性主闭藏，导致腠理（皮肤纹理及汗孔）闭合致密，阳气被郁遏而不能通畅运行，郁结于内化热，因此身体发热、干燥且无汗。所以经文说：“人受寒邪侵袭，就会发生热病。”又说：“所有热病都属于伤寒的范畴。”《内经》直接称其为“热病”，是指全身出现的病理性热气；而张仲景直接称其为“伤寒”，是指外来的寒邪，以此区分风、寒、暑、湿等不同邪气的伤害，因为主治方法不同，所以只说“伤寒”，而不泛称为“热病”。寒邪造成的危害极大，所以一切内外所伤，凡是表现为发热出汗的热病，都统称为“伤寒”。又称之为“大病”，都是认为其危害巨大。另外，春季发生的称为温病，夏季发生的称为热病，秋季发生的称为湿病，冬季发生的称为伤寒。“伤寒”是随着四季天气的变化——春温、夏热、秋湿、冬寒而得名，用以说明四季疾病程度的轻重以及治疗方法的细微差别，大体上是一致的，并非指外伤和内病有本质的区别。有人说：冬天寒邪潜伏在肌肤骨肉之间，到了春天变为温病，夏天变为热病，秋天变为湿病，冬天变为正伤寒病；或者感受了寒邪但体内产生郁热，热势轻微而没有立即发病，等到将来阳气变动时，或者再次感邪而成为热病，这并不是说潜伏的寒气反而变成了热。经文说：“冬天受寒，春天必定发生温病。”也是这个意思。也有一时感受寒邪就立即成为热病的，或者是感受四时不正乖戾之气，或者是随着运气兴衰变动，或者是内外各种邪气伤害，或者是因其他病变成，或者是他人传染都能形成这些病，只是根据门类随证治疗罢了。经文所说的这六经传变，是外感寒邪导致热病的概况，也是治疗的主要法则。大法说：“伤寒第一天，太阳经受邪，所以头项疼痛，腰脊僵硬。”这是足太阳膀胱经的病证，所以经文说第五天足少阴肾水与之互为表里。有人说这是手太阳经，是错误的。这是六经的病证，有人据此直接说伤寒不传手经，也是错误的。难道没有详细阅读《热论》说五脏六腑都会受病吗？《刺热篇》也都讲五脏热病。只是因为热病多发生在足经，而在手经发病较少且病情轻微，且与足经略有兼证关系，发汗和攻下的治疗，只需分辨表里，所以不单提手经，而是附属于足经而言。如果是针刺治疗，则对本经进行补泻，分别针对五脏手足各经。
第二天阳明经受邪，所以身体发热、眼睛疼痛、鼻子干燥，无法入睡。
第三天少阳经受邪，所以胸胁疼痛且耳聋。
第四天太阴经受邪，所以腹部胀满且咽喉干燥。
第五天少阴经受邪，所以眼睛干燥、舌头干燥且口渴。
第六天厥阴经受邪，就会出现心烦腹满、睾丸收缩。
有人说如果传入手厥阴心包络相火，则水火既济而痊愈；如果传入足厥阴肝经，则土败木贼而死亡，这是荒谬的说法。这里经文讲的是足厥阴肝经的病证。
大法说：“前三天是三阳病，病位在表，所以适宜用发汗法。”
通过发汗泄热，热退身凉而痊愈。
后三天是三阴病，病位在里，所以适宜用攻下法。
通过攻下，清除里热，使郁热宣通，出汗且气血调和而痊愈。也有里热攻下已尽，不出汗但气血调和而痊愈的情况。有人说“前三天寒邪在表”，这是错误的。这些都是热证。
如果病未愈，经过一个周期后衰退，第七天太阳病衰退（以下皆言病自衰减），头项痛稍好转；第八天阳明病衰退，身体发热稍好转；第九天少阳病衰退，耳朵能微微听到声音；第十天太阴病衰退，身体发热稍好转，腹部依然胀满；第十一天少阴病衰退，口渴停止、腹部不再胀满（即腹部不再胀满），舌头干燥，随后打喷嚏；第十二天厥阴病衰退，睾丸松弛、小腹微降，大气（指大病的热气）全部散去，病就好了。
这也是大概的说法，患伤寒不必拘泥于此，只是为了阐明各种证候并依法治疗罢了。
The classic states: Cold damages the form, cold damages the skin and hair, cold damages the blood, and cold damages the Ying (Nutritive Qi). However, cold governs closure and storage, causing the Couli (skin pores and interstices) to close tightly. The Yang Qi is constrained and cannot circulate freely, stagnating internally to generate heat. Therefore, the body becomes hot, dry, and anhidrotic (without sweat). Thus, the classic says: "When humans are injured by cold, it manifests as a febrile disease." It also states: "All febrile diseases belong to the category of Shanghan (Cold Damage)." The *Neijing* (*Inner Canon*) directly refers to them as "Febrile Diseases," indicating the pathological heat throughout the body; whereas Zhang Zhongjing directly refers to them as "Shanghan," indicating the external pathogenic cold. This distinction separates the injuries caused by Wind, Cold, Summerheat, and Dampness, as their primary treatments differ. Hence, only "Shanghan" is mentioned, not broadly "Febrile Disease." The harm caused by cold pathogens is immense; therefore, all internal and external injuries that manifest as febrile diseases with sweating are collectively termed "Shanghan." They are also called "Da Bing" (Great Illness), signifying their significant harm. Furthermore, those occurring in Spring are called Wenbing (Warm Disease), in Summer Rebing (Heat Disease), in Autumn Shibing (Damp Disease), and in Winter Shanghan. "Shanghan" is named according to the seasonal weather changes—Spring warmth, Summer heat, Autumn dampness, Winter cold—to clarify the severity of diseases in different seasons and the nuances of treatment. Broadly speaking, they are one and the same, not implying a fundamental difference between external injuries and internal diseases. Some claim that cold pathogens lie dormant in the skin, flesh, and bones during Winter, transforming into Warm Disease in Spring, Heat Disease in Summer, Damp Disease in Autumn, and proper Shanghan in Winter. Or, one may contract cold but develop internal constrained heat; if the heat is mild, illness does not occur immediately. Later, when Yang heat shifts, or upon re-infection, it becomes a febrile disease. This does not mean the latent cold transforms into heat. The classic says: "Injured by cold in Winter, one will surely suffer from Warm Disease in Spring." This aligns with this principle. There are also cases where contracting cold immediately results in a febrile disease, due to contracting abnormal and chaotic Qi of the four seasons, changes in Qi dynamics, injury from various internal and external pathogens, transformation from other diseases, or contagion from others. These are treated by categorizing and addressing symptoms accordingly. The classic's discussion on the transmission through the Six Channels outlines the general pattern of external cold leading to febrile disease and the essential methods of treatment. The great principle states: "On the first day of Shanghan, the Taiyang channel receives the pathogen, resulting in headache and stiffness of the neck and spine." This refers to the Foot-Taiyang Bladder Channel. Thus, the classic states that on the fifth day, the Foot-Shaoyin Kidney Water acts as its interior-exterior pair. To say it is the Hand-Taiyang channel is incorrect. These are the syndromes of the Six Channels. To claim based on this that Shanghan does not transmit to the Hand channels is also incorrect. Did one not carefully read the *Re Lun* (*Treatise on Febrile Diseases*), which states that all Zang and Fu organs can be diseased? The *Ci Re Pian* (*Chapter on Acupuncture for Heat*) also discusses heat diseases of the Five Zang organs. It is simply that febrile diseases occur more frequently in the Foot channels, while involvement of the Hand channels is less common and milder, often appearing as minor concurrent syndromes with the Foot channels. For treatments involving sweating or purging, one only distinguishes between exterior and interior, so the Hand channels are not mentioned separately but are subsumed under the Foot channels. In acupuncture, however, tonification and reduction are applied to the specific meridians of each Zang organ and Hand/Foot channels.
On the second day, the Yangming channel receives the pathogen, resulting in fever, eye pain, nasal dryness, and insomnia.
On the third day, the Shaoyang channel receives the pathogen, resulting in hypochondriac pain and deafness.
On the fourth day, the Taiyin channel receives the pathogen, resulting in abdominal fullness and dry throat.
On the fifth day, the Shaoyin channel receives the pathogen, resulting in dry eyes, dry tongue, and thirst.
On the sixth day, the Jueyin channel receives the pathogen, resulting in vexation, abdominal fullness, and contraction of the genitals.
To claim that transmission to the Hand-Jueyin Pericardium Sanjiao (Triple Burner) leads to the balance of Water and Fire and recovery, or that transmission to the Foot-Jueyin Liver channel leads to the failure of Earth and the attack of Wood resulting in death, is absurd talk. This passage describes the syndrome of the Foot-Jueyin Liver channel.
The great principle states: "For the first three days, the disease involves the Three Yang channels and is at the exterior, so sweating therapy is appropriate."
Sweating releases the heat; when the fever subsides and the body cools, recovery occurs.
"For the last three days, the disease involves the Three Yin channels and is at the interior, so purging therapy is appropriate."
Purging eliminates interior heat, allowing the constrained heat to dissipate and circulate freely. Recovery occurs with sweating and harmonized Qi. There are also cases where interior heat is exhausted via purging, no sweating occurs, yet Qi harmonizes and recovery ensues. To say "for the first three days, cold is at the exterior" is incorrect. These are all heat syndromes.
If the disease has not resolved, after another cycle, it begins to wane. On the seventh day, the Taiyang disease wanes (from here on, it refers to the natural decline of the disease); the head and neck pain improves slightly. On the eighth day, the Yangming disease wanes; body fever improves slightly. On the ninth day, the Shaoyang disease wanes; hearing returns slightly. On the tenth day, the Taiyin disease wanes; body fever improves slightly, but abdominal fullness remains as before. On the eleventh day, the Shaoyin disease wanes; thirst stops, abdominal fullness ceases (meaning the abdomen is no longer distended), tongue dryness persists, followed by sneezing. On the twelfth day, the Jueyin disease wanes; the genitals relax, the lower abdomen descends slightly, and the "Da Qi" (great pathogenic heat) disperses completely. The illness is cured (Chou, meaning recovered).
This is a general statement. One need not rigidly adhere to this timeline for Shanghan, but rather use it to understand the various syndromes and treat them according to the principles.