平旦至日中天之阳。阳中之阳也。日中至黄昏。天之阳。阳中之阴也。合夜至鸡鸣。天
之阴。
也。自酉时日入地中为夜。天之阴也。然于阴阳之中。复有阴阳如此)故人亦应之。夫言人
之阴阳。则外为阳。内为阴。言人身之阴阳。则背为阳。腹为阴言人身之脏腑中阴阳。则脏
者为阴腑者为阳。肝心脾肺肾五脏皆为阴。胆胃大肠小肠膀胱三焦。六腑皆为阳。故背为阳
。阳中之阳心也。背为阳。阳中之阴肺也。腹为阴阴中之阴肾也。腹为阴。阴中之阳肝也
腹为阴阴中之至阴脾也此皆阴阳表里内外雌雄相输应也故以应天之阴阳也。
阴阳者。天地之道也。(天生于动。地生于静)万物之纲纪(总之为纲周之为纪)变化之父
母(物生谓之化。物极谓之变。皆阴阳之所生。故为父母)生杀之本始(本根本。始终始也)神明
之府也(神。变化不测也。明。三光着象也。府所以藏物也。神明出于阴阳故阴阳为神明之
府)治病必求于本(天地万物变化生杀而神明者皆本于阴阳。病所从生。皆不外阴阳二气。或
本于阴。或本于阳。必求其故而施治也)故积阳为天。积阴为地。阴静阳躁阳生阴长阳杀阴
藏(阳不独立。必得阴而后成。如阳和发生。雨露长养。是阳生阴长也。阴不自专。必因阳
而后行。如寒列闭藏。风霜肃杀。是阳杀阴藏也)阳化气(阳动而散)阴成形(阴静而疑)寒极
生热。热极生寒(阴极则阳生。阳极则阴生)寒气生浊。热气生清(寒气疑滞故生浊阴热气升
散。故生清阳)清气在下。则生飧泄浊气在上。则生 胀(清阳陷于下而不能升。故为飧泄。
浊阴逆于上而不能降。故为 胀。由膻中不化气。胸膈满也)此阴阳反作。病之逆从也(阴阳
相反。清浊易位。则为逆。顺则为从也)故清阳为天。浊阴为地。地气上为云。天气下为雨
。雨出地气云出天气(天地者。阴阳之形体也。云雨者。天地之精气也。阴在下为精。即水
也精升则化为气。阳在上者为气。即云也。气降则化为精。故又曰雨出地气。云出天气。出
通也)故清阳出上窍浊阴出下窍(本乎天者亲上本乎地者亲下)清阳发腠理浊阴走五脏清阳实
四肢浊阴归六腑(阳主外。阴主内)水为阴火为阳(人身之水火)阳为气阴为味(药食气味)味归
形。形归气。气归精。精归化(形食味。故味归形。气生形。故形归气。精食气。故气归精
。化生精故精归化)精食气形食味(气和精生。味和形长)化生精。气生形(精生于运化之神。
形生于无形之气○前言精归化者。未化之前由精为化也。此言化生精者。既化之后。由化生
精也)味伤形。气伤精(味太过则偏胜故伤形气有余。便是火。故伤精)精化为气(元气由精而
化)气伤于味(食伤则气怠)阴味出下窍(味有质故下流)阳气出上窍(气无形故上达)味浓者为
阴薄为阴之阳。气浓者为阳薄为阳之阴(味为阴气为阳)味浓则泄。薄则通(味浓者能泄于下
味薄者能通利)气薄则发泄。浓则发热(气薄者能发散。气浓者能发热)壮火之气衰少火之气
壮(壮已必衰。少已必壮)壮火食气。气食少火。壮火散气。少火生气(火即气也。火壮则耗
散
元气。故壮火食气少火则生长元气。故气食少火)气味。辛甘发散为阳。酸苦涌泄为阴(此言
正味之阴阳)阴胜则阳病。阳胜则阴病。阳胜则热。阴胜则寒(阴阳偏胜之为病)重寒则热。
重热则寒(物极则变)寒伤形。热伤气气伤痛。形伤肿。故先痛而后肿者。气伤形也(气先病
而伤及于形)先肿而后痛者。形伤气也(形先病而伤及于气)风胜则动(振掉摇动之病)热胜则
肿(丹毒痈肿之病)燥胜则干(津液枯涸。内外干涩之病)寒胜则浮(寒胜则阳气不运。故胀
满虚浮)湿胜则濡泻(士不能制水。故为注泄○濡音如。湿滞也)喜怒伤气(言喜怒则悲忧恐同矣
)寒暑伤形(言寒暑则燥湿风同矣)
从清晨到日中，是白天的阳气，属于阳中之阳。从日中到黄昏，是白天的阴气，属于阳中之阴。从日落合夜到鸡鸣，是夜晚的阴气。自酉时太阳落入地平线以下进入地下，称为夜，这是天之阴。然而，在阴阳之中，又各自包含阴阳，正如上述情况一样，所以人也顺应这种规律。
说到人的阴阳，则体表为阳，体内为阴；说到人身躯的阴阳，则背部为阳，腹部为阴；说到人身脏腑中的阴阳，则脏者为阴，腑者为阳。肝、心、脾、肺、肾五脏皆为阴；胆、胃、大肠、小肠、膀胱、三焦六腑皆为阳。因此，背部属阳，其中的心是阳中之阳；背部属阳，其中的肺是阳中之阴；腹部属阴，其中的肾是阴中之阴；腹部属阴，其中的肝是阴中之阳；腹部属阴，其中的脾是阴中之至阴。这些都是阴阳、表里、内外、雌雄相互对应关联的，以此来顺应天地的阴阳变化。
阴阳，是天地运行的规律。（天由运动而生，地由静止而生），是万物的纲领和法度（总括为纲，周遍为纪），是万物变化的父母（事物生长称为化，事物发展到极点称为变，都由阴阳所产生，所以称为父母），是生杀存亡的根本起始（本即根本，始即开始），也是神明产生的府库（神，指变化莫测；明，指日月星辰显现形象；府，是储藏物品的地方。神明出于阴阳，所以阴阳是神明的府库）。治病必须探求根本（天地万物的变化、生杀及神明，都根源于阴阳。疾病的发生，都不外乎阴阳二气，有的根于阴，有的根于阳，必须探究其根源而施以治疗）。
所以，积聚的阳气上升形成天，积聚的阴气下沉形成地。阴气主静，阳气主动；阳气生发，阴气成长；阳气肃杀，阴气闭藏。（阳气不能独立存在，必须得到阴气才能成就，如温和之气发生，雨露滋润生长，这就是阳生阴长。阴气不能独自专行，必须依赖阳气才能运行，如寒冽之气闭藏，风霜肃杀，这就是阳杀阴藏）。阳气化生功能（阳气运动而发散），阴气构成形体（阴气静止而凝聚）。寒气极盛则生热，热势极盛则生寒（阴气至极则阳气生发，阳气至极则阴气生发）。寒气产生浊阴，热气产生清阳（寒气凝滞所以产生浊阴，热气升散所以产生清阳）。清阳之气如果在下部，就会发生完谷不化的泄泻；浊阴之气如果在上部，就会发生胸腹胀满。（清阳陷于下而不能上升，所以导致泄泻；浊阴逆于上而不能下降，所以导致胸膈胀满。这是由于膻中不能化气，导致胸膈满闷）。这就是阴阳反常作乱，疾病有逆证和顺证的区别（阴阳相反，清浊位置互换，就是逆证；顺则为从证）。
所以，清阳上升为天，浊阴下沉为地。地气上升成为云，天气下降成为雨。雨出自地气，云出自天气（天和地，是阴阳的形体；云和雨，是天地的精气。阴在下为精，即水；精上升则化为气，阳在上为气，即云；气下降则化为精。所以说雨出自地气，云出自天气，“出”通“由”的意思）。
所以，清阳出于上窍（眼耳鼻口），浊阴出于下窍（前后二阴）（本乎天的亲上，本乎地的亲下）。清阳发散于腠理，浊阴走注于五脏；清阳充实于四肢，浊阴归聚于六腑（阳主外，阴主内）。水属于阴，火属于阳（人体内的水火）。阳属于气，阴属于味（药物和食物的气味）。味道滋养形体，形体依赖气，气滋养精，精转化为气化（形体食用味道，所以味道归形；气生成形体，所以形体归气；精食用气，所以气归精；气化生精，所以精归化）。精食用气，形体食用味道（气和精相生，味和形相长）。气化生精，气生成形体（精生于运化之神，形生于无形之气。前文说“精归化”，是指未化之前由精转化为化；此处说“化生精”，是指既化之后，由化再生精）。味道过度会损伤形体，气有余会损伤精（味道太过则偏胜，所以损伤形体；气有余便是火，所以损伤精）。精可以转化为气（元气由精转化而来）。气会被味道所伤（饮食受伤则气怠惰）。阴味的物质从下窍排出（味道有形质，所以下流）；阳气的功能从上窍发出（气无形，所以上达）。味道浓厚的属于阴，味道淡薄的属于阴中之阳；气味浓厚的属于阳，气味淡薄的属于阳中之阴（味道为阴，气为阳）。味道浓厚能泄下，味道淡薄能通利（味道浓者能泄于下，味道薄者能通利）。气味淡薄能发散，气味浓厚能发热（气味薄者能发散，气味浓者能发热）。壮火会使元气衰退，少火会使元气强盛（壮火必衰，少火必壮）。壮火消耗元气，元气依赖少火；壮火散失元气，少火滋生元气（火即气也。火壮则耗散元气，所以壮火食气；少火则生长元气，所以气食少火）。
气味方面，辛、甘具有发散作用的属于阳；酸、苦具有涌吐、泄降作用的属于阴（这里说的是正味的阴阳）。阴气偏胜则阳气生病，阳气偏胜则阴气生病；阳气偏胜则表现为热证，阴气偏胜则表现为寒证（阴阳偏胜导致的疾病）。寒邪重则转化为热，热邪重则转化为寒（物极必反）。寒邪损伤形体，热邪损伤气；气病导致疼痛，形病导致肿胀。所以先痛后肿的，是气伤及形（气先病而伤及于形）；先肿后痛的，是形伤及气（形先病而伤及于气）。风邪偏胜则出现动摇之症（震颤摇动的病）；热邪偏胜则出现红肿之症（丹毒痈肿的病）；燥邪偏胜则出现干燥之症（津液枯涸，内外干涩的病）；寒邪偏胜则出现浮肿之症（寒胜则阳气不运，所以胀满虚浮）；湿邪偏胜则出现濡泄之症（土不能制水，所以为注泄。“濡”音同“如”，意为湿滞）。喜怒等情志会损伤气（提到喜怒，悲忧恐也同理）；寒暑等气候会损伤形体（提到寒暑，燥湿风也同理）。
From dawn to noon, it is the Yang Qi of the day, which belongs to Yang within Yang. From noon to dusk, it is the Yin Qi of the day, which belongs to Yin within Yang. From sunset and nightfall until the crowing of the rooster, it is the Yin of the night. Since You hour (5-7 PM), when the sun sets below the horizon into the earth, it is called night; this is the Yin of Heaven. However, within Yin and Yang, there are again Yin and Yang, as described above; thus, humans also correspond to this pattern.
When speaking of human Yin and Yang, the exterior is Yang and the interior is Yin. When speaking of the Yin and Yang of the human body, the back is Yang and the abdomen is Yin. When speaking of the Yin and Yang within the Zang-Fu organs, the Zang organs are Yin and the Fu organs are Yang. The Liver, Heart, Spleen, Lung, and Kidney (five Zang organs) are all Yin; the Gallbladder, Stomach, Large Intestine, Small Intestine, Bladder, and Sanjiao (Triple Burner) (six Fu organs) are all Yang. Therefore, the back is Yang; among them, the Heart is Yang within Yang. The back is Yang; among them, the Lung is Yin within Yang. The abdomen is Yin; among them, the Kidney is Yin within Yin. The abdomen is Yin; among them, the Liver is Yang within Yin. The abdomen is Yin; among them, the Spleen is Yin within Yin reaching its extreme (Zhiyin). These are all corresponding relationships among Yin-Yang, Interior-Exterior, Inside-Outside, and Male-Female, thereby responding to the Yin-Yang of Heaven.
Yin and Yang are the Dao (Way/Law) of Heaven and Earth. (Heaven arises from movement, Earth arises from stillness); they are the general principles and regulations of all things (summarized as Gang, encompassed as Ji); they are the parents of changes (growth of things is called Hua, extremity of things is called Bian, both generated by Yin-Yang, hence called parents); they are the root and beginning of life and death (Ben is root, Shi is beginning); they are the mansion where Shenming (Spiritual Illumination) resides (Shen refers to unpredictable changes; Ming refers to the manifestation of the three luminaries [sun, moon, stars]; Fu is a place for storing things. Shenming emerges from Yin-Yang, therefore Yin-Yang is the mansion of Shenming). Treating disease must seek the Ben (Root) (The changes, life/death, and Shenming of heaven and earth and all things are rooted in Yin-Yang. The origin of disease lies not outside the two Qi of Yin and Yang, either rooted in Yin or in Yang; one must seek its cause and apply treatment accordingly).
Thus, accumulated Yang Qi forms Heaven, and accumulated Yin Qi forms Earth. Yin is quiet, Yang is active; Yang generates, Yin grows; Yang kills (subdues), Yin stores. (Yang cannot exist independently; it must obtain Yin to complete itself, such as warm Qi generating and rain/dew nourishing, which is Yang generating and Yin growing. Yin cannot act alone; it must rely on Yang to proceed, such as cold Qi closing/storing and wind/frost subduing, which is Yang subduing and Yin storing). Yang transforms into Qi (Yang moves and disperses); Yin forms into Shape (Yin is still and coagulates). Extreme Cold generates Heat; extreme Heat generates Cold (Extreme Yin leads to the generation of Yang; extreme Yang leads to the generation of Yin). Cold Qi generates Turbid Yin; Hot Qi generates Clear Yang (Cold Qi is stagnant, thus generating Turbid Yin; Hot Qi ascends and disperses, thus generating Clear Yang). If Clear Yang is below, it generates Sundun diarrhea (undigested food in stool); if Turbid Yin is above, it generates abdominal distension. (Clear Yang sinks below and cannot ascend, thus causing Sundun diarrhea; Turbid Yin rebels upward and cannot descend, thus causing chest/diaphragm fullness/distension. This is due to the inability of Danzhong to transform Qi, leading to chest fullness). This is Yin-Yang acting in reverse, indicating the deviation or compliance of disease (Yin-Yang are opposite, Clear/Turbid positions are swapped, this is Deviation/Ni; compliance is Cong).
Thus, Clear Yang becomes Heaven, Turbid Yin becomes Earth. Earth Qi rises to become Clouds, Heaven Qi descends to become Rain. Rain comes from Earth Qi, Clouds come from Heaven Qi (Heaven and Earth are the physical forms of Yin-Yang; Clouds and Rain are the essence-Qi of Heaven and Earth. Yin below is Essence, i.e., Water; Essence rising transforms into Qi, Yang above is Qi, i.e., Clouds; Qi descending transforms into Essence. Hence it is said Rain comes from Earth Qi, Clouds come from Heaven Qi. "Chu" implies "from").
Thus, Clear Yang exits through the upper orifices, Turbid Yin exits through the lower orifices (That which is based on Heaven tends upward; that which is based on Earth tends downward). Clear Yang disseminates through the Couli (interstices/skin pores), Turbid Yin travels to the five Zang organs; Clear Yang fills the four limbs, Turbid Yin returns to the six Fu organs (Yang governs the exterior, Yin governs the interior). Water is Yin, Fire is Yang (Water and Fire in the human body). Yang is Qi, Yin is Flavor (Flavor and Qi of medicine and food). Flavor returns to/nourishes Shape; Shape returns to/nourishes Qi; Qi returns to/nourishes Essence; Essence returns to/nourishes Transformation (Shape consumes Flavor, hence Flavor returns to Shape; Qi generates Shape, hence Shape returns to Qi; Essence consumes Qi, hence Qi returns to Essence; Transformation generates Essence, hence Essence returns to Transformation). Essence consumes Qi, Shape consumes Flavor (Qi and Essence generate mutually; Flavor and Shape grow mutually). Transformation generates Essence, Qi generates Shape (Essence is born from the spirit of transformation; Shape is born from formless Qi. Previously mentioned "Essence returns to Transformation" refers to Essence transforming before transformation occurs; here "Transformation generates Essence" refers to Essence being generated after transformation has occurred). Excessive Flavor damages Shape; excess Qi damages Essence (Excessive flavor leads to bias and damage to Shape; excess Qi becomes Fire, thus damaging Essence). Essence transforms into Qi (Yuan Qi transforms from Essence). Qi is damaged by Flavor (Damage to food intake leads to Qi lethargy). Yin Flavor exits through the lower orifices (Flavor has substance, thus flows downward); Yang Qi exits through the upper orifices (Qi is formless, thus reaches upward). Strong Flavor is Yin; weak Flavor is Yang within Yin; Strong Qi is Yang; weak Qi is Yin within Yang (Flavor is Yin, Qi is Yang). Strong Flavor causes purgation; weak Flavor causes unblocking (Strong Flavor can purge downward; weak Flavor can promote circulation). Weak Qi causes dispersion/excretion; strong Qi causes fever (Weak Qi can disperse; strong Qi causes fever). Zhuang Huo (Blazing Fire) causes Qi to decline; Shao Huo (Mild Fire) causes Qi to strengthen (Blazing fire inevitably declines; mild fire inevitably strengthens). Zhuang Huo consumes Qi; Qi feeds on Shao Huo; Zhuang Huo scatters Qi; Shao Huo generates Qi (Fire is Qi. Blazing fire consumes/scatters Yuan Qi, hence Zhuang Huo consumes Qi; Mild fire grows Yuan Qi, hence Qi feeds on Shao Huo). Regarding Flavors and Qi: Acrid and Sweet with dispersing properties are Yang; Sour and Bitter with vomiting/purgative properties are Yin (This refers to the Yin-Yang of proper flavors). Yin excess leads to Yang disease; Yang excess leads to Yin disease; Yang excess leads to Heat; Yin excess leads to Cold (Disease caused by Yin-Yang excess). Heavy Cold transforms into Heat; heavy Heat transforms into Cold (Things at their extreme change). Cold damages Shape; Heat damages Qi; Qi pathology causes pain; Shape pathology causes swelling. Thus, pain followed by swelling indicates Qi damaging Shape (Qi diseased first, then damaging Shape); swelling followed by pain indicates Shape damaging Qi (Shape diseased first, then damaging Qi). Wind excess causes tremors/movement (diseases of shaking/trembling); Heat excess causes swelling (erysipelas/abscess diseases); Dryness excess causes dryness (withering of fluids, internal/external dryness diseases); Cold excess causes floating/swelling (Cold excess impedes Yang Qi transport, thus causing fullness/virtual swelling); Dampness excess causes loose diarrhea (Earth fails to control Water, thus causing projectile diarrhea. "Ru" sounds like "ru", meaning damp stagnation). Joy and anger damage Qi (Mentioning joy and anger, sadness, worry, and fear are similar); Cold and heat damage Shape (Mentioning cold and heat, dryness, dampness, and wind are similar).