冬伤于寒者。冬行秋令也。当寒而温火胜而水亏矣水既已亏则所胜妄行。土有余也。所
生受病
。水不足也。所不胜者侮之。火太过也。火土合德。湿热相助。故为温病。使民腠理开泄。
少阴不藏。惟房室劳伤。辛苦之人得之。若此者皆为温病。所以不病于冬。而病于春者以其
寒水居卯之分方得其权。大寒之令复行于春。腠理开泄。少阴不藏。房室劳伤。辛苦之人。
阳气泄于外。肾水亏于内。当春之月。时强木长无以滋生化之源。故为温病耳。故君子周密
于冬。少阴得藏于内腠理以闭拒之虽有大风苛毒莫之能害矣。何温病之有哉。人肖天地而生
也。冬时阳气俱伏
于九泉之下。人之阳气俱藏于一肾之中。人能不扰乎肾。则六阳安静于内。内既得以安。外
无自而入矣。此伤寒之源。非天之伤人。乃人自伤也。伤于寒者皆为病热。为伤寒气乃热病
之总称。故曰伤寒。知寒受热邪明矣。六阴用事于冬。阳气在内周密闭藏可矣。反劳动之。
而泄于外。时热已伤于水矣。至春之时。木当发生阳已外泄。孰为鼓舞。肾水内竭。孰为滋
养。此两者同为生化之源。源既已绝。水何赖以生乎。身之所存者。独有热也时强木长。故
为温病矣。
木在时为春。在人为肝。在天为风。风者无形之清气也。当春之时发为温令。反为寒折
。
是三春之月。行严冬之令也。以是知水为大过矣。水既太过。金肃愈□是所胜者乘之而妄行
也
。所胜者乘之。则木虚明矣故经曰。从后来者为虚邪。木气既虚。火令不及是所生者受病也
。
故所不胜者侮之。是以土来木之分 而为飧泄也。故经曰。清气在下。则生飧泄以其湿令
当权。故飧泄之候发之于夏也。若当春之时。木不发生。
温令未显。止行冬令。是谓伤卫。以其阳气不出地之外也。当以麻黄汤发之。麻黄味苦。味
之薄者。乃阴中之阳也。故从水中补木而泻水。发出津液为汗也。若春木已生。温令已显。
阳气出于地之上。寒再至而复折之当以轻发之。谓已得少阳之气。不必用麻黄也。春伤于风
。夏生飧泄。所以病发于夏者。以其木绝于夏。而土旺于长夏。湿本有夏行之体。故飧泄于
夏也。不病于春者。以其春时风虽有伤。木实当权。故飧泄不病于木之时。而发于湿之分也
。经曰至而不至。是为不及。所胜妄行。所不胜者薄之。所生者受病。此之谓也。
冬季感受寒邪，是因为冬季行秋季的时令。应当寒冷的时候，却因温热之火偏胜而导致肾水亏虚。既然肾水已经亏虚，那么被水所克的土气就会妄行（即脾土有余）。由于土气有余，它所生的金气就会受到牵连而致病；同时，因为肾水不足，克制水的火气就会反过来欺侮水气（即火气太过）。火与土结合其德性，湿热相互助长，因此形成温病。这使得百姓腠理（皮肤毛孔）开泄，少阴肾气不能闭藏。这种情况多见于房事过度或劳累损伤的人。凡是这类情况都属于温病。之所以不在冬季发病而在春季发病，是因为在冬季（对应地支卯位之前的时段），寒水之气本应占据主导权，但此时大寒的时令反而在春季重现。腠理开泄，少阴不藏，加上房劳和辛苦劳作，导致阳气外泄，肾水内亏。到了春季，当令的木气强盛生长，却无法滋养化生之源，所以产生温病。因此，君子在冬季应当周密保养，使少阴之气在内得以闭藏，腠理闭合以抵御外邪，即使有大风剧毒也不能伤害他，哪里还会有温病呢？人禀受天地之气而生，冬季时阳气都潜伏在九泉之下，人的阳气也都藏在一肾之中。人如果不扰动肾脏，那么六阳经的气机就能在内保持安静。内部既已安宁，外部邪气自然无法侵入。这就是伤寒的根源，并非天灾伤人，而是人自我损伤。感受寒邪最终都会转化为热病，“伤寒”是伤寒气乃热病的总称。所以说“伤寒”，可知寒邪入体后受热邪影响是很明显的。
冬季由六阴主事，阳气在内周流密闭收藏才是正确的。如果反而进行劳动使其耗散并外泄，此时体内的热邪已经损伤了肾水。到了春季，木气应当生发，但阳气已经外泄，谁去鼓舞生机？肾水在内枯竭，谁去滋养身体？这两者都是化生之源，源头既然断绝，水又依靠什么来生成呢？身体里存留的只有热邪，加之当令的木气强盛生长，所以形成温病。
木在季节上对应春季，在人体对应肝脏，在天对应风气。风是一种无形的清气。在春季之时，本该发出温暖的时令，却反被寒邪折损。这是说三个月的春季，行的是严冬的时令。由此可知水气太过严重。水气既已太过，金气的肃杀之气就会更加旺盛（此处原文有缺字，意指金气受制或乘势），这是被克者（木）被乘虚而入而妄行。被克者妄行，则木气虚弱就显而易见了。所以《内经》说：“从后来者为虚邪。”木气既然虚弱，火令不及，这是其所生者（火）受病。因此，克制木的土气就会欺侮它（即土来乘木）。所以《内经》说：“清气在下，则生飧泄。”因为湿令当时掌权，所以飧泄的症状在夏季发作。如果在春季，木气不生发，温令未显现，只行冬令，这叫做伤卫气。因为阳气不出于地表之上。此时应当用麻黄汤发散。麻黄味苦，气味轻薄，属于阴中之阳。所以能从水中补益木气而泻除水气，通过发出津液为汗来解表。如果春木已经生发，温令已经显现，阳气出于地表之上，寒邪再次到来并折损它，应当用轻剂发散。因为此时已获得少阳之气，不必使用麻黄。
春季伤于风邪，夏季发生飧泄。之所以在夏季发病，是因为木气在夏季绝灭，而土气在长夏旺盛。湿气本具有在夏季运行的特性，所以飧泄在夏季发作。不在春季发病，是因为春季时风邪虽然伤人，但木气实际上当权，所以飧泄不在木气当令之时发病，而是在湿气当令之时发作。《内经》说：“至而不至，是为不及。所胜妄行，所不胜者薄之，所生者受病。”说的就是这个道理。
Winter injury by cold pathogens occurs because winter follows the climate of autumn. When it should be cold, the fire of warmth prevails excessively, leading to a deficiency of Kidney Water (Shen Shui, 肾水). Since Kidney Water is already deficient, the element controlled by water (Earth/Spleen) acts recklessly, resulting in an excess of Earth. Because Earth is in excess, the element generated by Earth (Metal/Lung) suffers disease. Meanwhile, due to the insufficiency of Water, the element that controls Water (Fire/Heart) insults it, leading to an excess of Fire. Fire and Earth combine their virtues, with damp-heat assisting each other, thus forming Warm Disease (Wen Bing, 温病). This causes the people's Cou Li (pores/skin texture, 腠理) to open and leak, and the Shaoyin (Kidney channel, 少阴) fails to store essence. This condition mostly affects those who suffer from excessive sexual activity or laborious hardship. All such cases belong to Warm Disease. The reason for not falling ill in winter but in spring is that during winter (associated with the Mao position), Cold Water energy should hold authority, yet the severe cold command reappears in spring. With Cou Li open and Shaoyin failing to store, combined with sexual labor and physical exertion, Yang Qi leaks outward while Kidney Water depletes inward. In spring, when Wood Qi grows strongly, it cannot nourish the source of generation and transformation, hence producing Warm Disease. Therefore, gentlemen should be meticulous in winter, allowing Shaoyin Qi to store internally and Cou Li to close and resist external evils; even strong winds and severe toxins cannot harm them, so how could there be Warm Disease? Humans are born resembling heaven and earth. In winter, Yang Qi hides beneath the nine springs, and human Yang Qi stores within one Kidney. If humans do not disturb the Kidney, the six Yang meridians remain quiet internally. Once the interior is peaceful, external pathogens have no entry. This is the origin of Cold Damage (Shang Han, 伤寒); it is not heaven injuring people, but people injuring themselves. Injury by cold pathogens all leads to heat diseases; "Cold Damage" is the general term for heat diseases caused by cold pathogens. Thus, "Cold Damage" implies that knowing cold and receiving heat pathogens is clear.
In winter, the six Yin energies govern, and Yang Qi circulates internally, closed and stored properly. If one instead labors and causes leakage outward, the internal heat has already damaged Water. By spring, Wood should generate life, but since Yang Qi has leaked outward, who will encourage growth? Kidney Water is exhausted internally, who will nourish the body? Both are sources of generation and transformation; once the source is cut off, on what does Water rely to be produced? What remains in the body is only heat. Coupled with the strong growth of Wood Qi in season, Warm Disease arises.
Wood corresponds to Spring in seasons, Liver in humans, and Wind in heaven. Wind is a formless pure Qi. In spring, the warm command should emerge, but it is instead restrained by cold. This indicates that in the three months of spring, the strict command of deep winter prevails. From this, we know Water is excessively strong. Since Water is too strong, Metal's肃杀 (astringent/descending) nature becomes extreme (text missing character, implying Metal overacts or is affected), which is the controlled element acting recklessly due to being overwhelmed. When the controlled element acts recklessly, Wood deficiency becomes obvious. Hence, the Classic says: "Coming from behind is empty evil." Since Wood Qi is weak, Fire's command is insufficient, meaning the element generated by Wood (Fire) suffers disease. Consequently, the element that controls Wood (Earth) insults it. Thus, Earth invades Wood's domain, causing Sundun Diarrhea (Sun Xie, 飧泄 - undigested food diarrhea). The Classic says: "Pure Qi below generates Sundun Diarrhea." Because Dampness commands power, Sundun Diarrhea symptoms appear in summer. However, if in spring, Wood does not generate, the warm command is not manifest, and only winter's command runs, this is called injuring Wei Qi (Defensive Qi, 卫气), because Yang Qi does not rise above the earth. At this time, Mahuang Tang (Ephedra Decoction) should be used to release the exterior. Mahuang (Ephedrae Herba, 麻黄) is bitter in taste and thin in aroma, belonging to Yang within Yin. Thus, it supplements Wood from Water and drains Water, releasing fluids as sweat. If spring Wood has already generated and the warm command is manifest, with Yang Qi emerging above the earth, and cold arrives again to restrain it, light release methods should be used. Since Shaoyang Qi has been obtained, Mahuang is unnecessary.
Spring injury by wind leads to Sundun Diarrhea in summer. The reason for onset in summer is that Wood Qi perishes in summer, while Earth Qi prospers in late summer. Dampness inherently possesses the nature of operating in summer, hence Sundun Diarrhea occurs in summer. It does not occur in spring because although wind injures in spring, Wood actually holds authority. Thus, Sundun Diarrhea does not manifest when Wood is in charge, but when Dampness is in charge. The Classic says: "Arriving but not arriving signifies insufficiency. The controlling element acts recklessly, the controlling-by-restriction element oppresses, and the generated element suffers disease." This refers to exactly this principle.