东垣谓百病之源，皆由喜怒、饮食、劳役所伤脾胃而然。其元气、谷气、营气；清气、
卫气、生发诸阳之气，此六者皆胃气之别称也。脾胃既伤，则中气不足；中
气不足，则不能滋养元气；不能滋养元气，则脏腑之真气皆不足，惟阴火独旺，上乘阳分无形
质，元气受病矣！系在上焦心肺之气绝于外，心主荣，肺主卫，故荣卫失守，诸病生焉！此论发热
尽由于内伤也，及河间所言则又不止此也。曰∶天真者，造化之元气也，在身亦得执天机而行六气，
分地纪而运五行，巡历周身，化生万物。若调摄适宜，邪不能伤，或忧愁思虑、饥饱劳逸、大惊卒恐，
真气耗乱，血气分离，其五行六气遂有愆阳伏阴兴衰之变，则百病作矣！于是着《原病式》以明其道，
取《至真要大论》之病机以为提纲；用五运主病者以言五脏所属木火土金水之变；用六气为病者以言三
阴三阳所属风寒湿热燥火气之变。在五行，则以金水易衰，火木易盛；在六气，则以湿热相火二气为
病独多。至于五行过极，亢则害，承乃制，反兼鬼贼之化，此皆得为发热之病，岂止由于脾胃所始乎？
先生不以一家之学自至，益求其未至。乃
谓天之阳，大于地之阴；地之阴，常不敌夫天之阳。人禀天之阳为气，地之阴为血，所以气常
有余，血常不足，此年四十而阴气已衰半矣！故人不可恣欲以自戕，必保养天和，庶几阴无亏缺，
可与阳齐，以终天年。夫天和者，天真元气也。负阴抱阳，元精立其体，元神致其用。苟不摇其精，则
体全而用不竭；不劳其神，则用专而体不亏。然精之秘，非惟奉养天真而已，精秘则阴实。经曰∶
阴成形。阴实则形全，阴虚则形敝，敝则出入废、升降息，孤阳之气安得不亢而飞越乎？先生尝曰∶人
因喜怒、劳役、色欲之火，煎熬肾水、枯竭精血而病者十常六七。夫五脏皆属阴而藏精者也，肾又五脏阴气
之主，故受五脏之精而藏之，故诸阴精血之病皆本于肾。其输纳之际必详察焉！大抵
效仲景八味丸以五味各入五脏益其精，其中桂、附之辛开腠理、致津液、通气道，输而与之。补肾之法，固
不越规矩，然地道之阴虚，则天道之阳不降，或阳乱于下而少阴之气不得收藏者，或精绝辟积而不输者，
或两肾阴阳自有偏者，必皆揆度以治。然元气者，在身有根有苗，在太虚非阴非阳。其根也自天地开发，
周流上下四方，随其所至以化行者，仲景所谓五脏元真是也。在肝则温化，其气升；在心则热化、其气浮；
在脾则冲和之化，其气备；在肺则凉化，其气降；在肾则寒化，其气藏∶犹天以一元之气行于四时也。
此苗也，各从其本脏之元真而论治。元气所化者不足，则从其所化补之；元真所化者太过，则反其所
化泻之。然则论元气独在脾胃者’此重水谷以资天真也。先生兼之受精以全角者，则又重两肾为元精，
立寿命本始之地也。钱仲阳于肾有补无泻，正此意耳！二者皆从根本而治也。
李东垣认为，百病的根源，都在于喜怒、饮食、劳役损伤了脾胃。元气、谷气、营气；清气、卫气、生发诸阳之气，这六种气都是胃气的不同称呼。脾胃一旦受伤，中气就会不足；中气不足，就不能滋养元气；不能滋养元气，脏腑的真气就都会不足，只有阴火独自旺盛，向上侵犯属阳的部位（无形质），元气因此患病！这表现为上焦心肺之气在体表衰竭，心主荣气，肺主卫气，所以荣卫失去固守，各种疾病由此产生！这种观点认为发热完全由于内伤引起，而刘河间所说的则不止于此。他说：天真，就是造化的元气，在人体内也能执掌天机运行六气，划分地纪运化五行，巡行周身，化生万物。如果调摄适宜，邪气不能伤害人体；若是忧愁思虑、饥饱劳逸不当、大惊大恐，导致真气耗散紊乱，血气分离，那么五行六气就会出现亢阳伏阴、兴衰变化的情况，百病就产生了！于是撰写《原病式》来阐明这一道理，选取《黄帝内经·素问·至真要大论》中的病机作为提纲；用五运主病来说明五脏所属木、火、土、金、水的变化；用六气为病来说明三阴三阳所属风、寒、湿、热、燥、火的变化。在五行方面，金和水容易衰弱，火和木容易旺盛；在六气方面，湿热和相火两种气致病最多。至于五行过极，亢盛则为害，需要有制约才能平衡，反而兼有克制它的“鬼贼”之化，这些都可以成为发热的病症，哪里仅仅是由脾胃开始的呢？
先生不局限于一家之学，而是不断探求尚未达到的境界。他认为天的阳气大于地的阴气；地的阴气，常常敌不过天的阳气。人禀受天的阳气化为气，禀受地的阴气化为血，所以气常有余，血常不足，因此人到四十岁阴气就已经衰退一半了！所以人不可放纵欲望自我残害，必须保养天和，这样阴气才没有亏缺，能与阳气齐平，从而终享天年。所谓天和，就是天真元气。背负阴怀抱阳，元精确立其形体，元神发挥其作用。如果不扰动精气，则形体完备而功能不竭；不劳累心神，则功能专注而形体不亏损。然而精气的秘藏，不仅仅是奉养天真而已，精气秘藏则阴实。经书说：阴成形。阴实则形体健全，阴虚则形体败坏，败坏则出入废弛、升降停止，孤阳之气怎能不亢盛而飞越呢？先生曾说：人因为喜怒、劳役、色欲之火，煎熬肾水、枯竭精血而患病的，十有六七。五脏都属于阴并贮藏精液，肾又是五脏阴气的主宰，所以接受五脏的精液而贮藏它，因此各种阴精血的病变都根源于肾。在治疗时对于肾脏的输纳功能必须详细考察！大体上效法张仲景的八味丸，利用五味各入五脏以增益其精，其中桂枝、附子的辛味能开泄腠理、输送津液、通畅气道，从而将药力输送到肾。补肾的方法，固然离不开规矩法度，但是如果是地道之阴虚，则天道之阳不能下降，或者阳气乱于下导致少阴之气不能收藏，或者精气枯竭积累而不能输布，或者两肾阴阳自有偏颇，都必须通过揣度病情来治疗。
然而元气，在体内有根有苗，在太虚之中非阴非阳。它的根源自天地开辟以来，周流于上下四方，随着所到达的地方而变化运行，这就是张仲景所说的五脏元真之气。在肝脏则温化，其气上升；在心则热化，其气浮越；在脾则冲和之化，其气具备；在肺则凉化，其气下降；在肾则寒化，其气闭藏：就像天以一元之气运行于四季一样。这个苗，各自从其本脏的元真来论述治疗。元气所化生的不足，就从其所化生的脏腑进行补益；元真所化生的太过，就反其道而行之进行泻除。既然这样，那么讨论元气独在脾胃，这是重视水谷以资助天真。先生又结合受精以成全角质的理论，则是重视两肾为元精，确立寿命根本起始之地。钱乙（钱仲阳）对于肾只有补法没有泻法，正是这个意思！这两种方法都是从根本上来治疗的。
Li Dongyuan stated that the root of all diseases lies in the damage to the Spleen and Stomach caused by emotions (joy and anger), diet, and overwork. Yuan Qi (Original Qi), Gu Qi (Grain Qi), Ying Qi (Nutritive Qi); Qing Qi (Clear Qi), Wei Qi (Defensive Qi), and the various Yang Qi of generation—these six are all alternative names for Wei Qi (Stomach Qi). Once the Spleen and Stomach are injured, Zhong Qi (Middle Qi) becomes insufficient; if Zhong Qi is insufficient, it cannot nourish Yuan Qi; if Yuan Qi is not nourished, the True Qi of the Zang-Fu organs will all be deficient, while Yin Fire alone flares up, attacking upward into the Yang regions (formless aspects), causing disease in Yuan Qi! This manifests as the Qi of the Upper Jiao (Heart and Lungs) failing externally at the body surface; since the Heart governs Ying Qi (Nutritive Qi) and the Lungs govern Wei Qi (Defensive Qi), Ying and Wei lose their guardianship, giving rise to various diseases! This theory posits that fever arises entirely from internal injury, whereas Liu Wansu’s (Hejian) discussion extends beyond this. He said: Tian Zhen (Innocent Truth/Primordial Essence) is the creative Yuan Qi. Within the body, it also executes the Heavenly Mechanism to circulate the Six Qi, divides the Earthly Register to operate the Five Elements, tours the entire body, and transforms into all things. If regulation and care are appropriate, pathogenic factors cannot harm the body; however, if there is worry, sorrow, excessive thought, irregular eating or fasting, overexertion or idleness, sudden great fright or terror, the True Qi will be consumed and chaotic, Blood and Qi will separate, and the Five Elements and Six Qi will undergo changes of hyperactive Yang, hidden Yin, decline, and prosperity, thus causing a hundred diseases! Therefore, he wrote *Yuan Bing Shi* (Treatise on the Origin of Diseases) to clarify this principle, taking the Pathogenesis from *Zhi Zhen Yao Da Lun* (The Most Essential Great Discussion) of the *Huangdi Neijing* as the outline; using the Five Movements (Wu Yun) governing diseases to discuss the variations of Wood, Fire, Earth, Metal, and Water associated with the Five Zang; using the Six Qi causing diseases to discuss the variations of Wind, Cold, Dampness, Heat, Dryness, and Fire associated with the Three Yin and Three Yang. In terms of the Five Elements, Metal and Water tend to decline, while Fire and Wood tend to flourish; in terms of the Six Qi, Damp-Heat and Ministerial Fire cause the most diseases. As for the Five Elements reaching extremes, hyperactivity causes harm, and restraint brings balance, sometimes involving transformations of the "Ghost-Thief" (controlling element); these can all result in fever-causing conditions, not merely those originating from the Spleen and Stomach?
Master Dai did not confine himself to one school of thought but continually sought areas yet unmastered. He asserted that Heaven’s Yang is greater than Earth’s Yin; Earth’s Yin often cannot withstand Heaven’s Yang. Humans inherit Heaven’s Yang to form Qi, and Earth’s Yin to form Blood; therefore, Qi is often in excess, while Blood is often deficient. Thus, by age forty, Yin Qi has already declined by half! Hence, humans must not indulge desires to self-harm, but must preserve Tian He (Heavenly Harmony), so that Yin suffers no deficiency, allowing it to equal Yang, thereby completing the natural lifespan. Tian He refers to Tian Zhen Yuan Qi. It carries Yin and embraces Yang; Yuan Jing (Original Essence) establishes its substance, and Shen Yuan (Spiritual Mind) exerts its function. If one does not agitate the Essence, the substance remains complete and function unexhausted; if one does not weary the Spirit, the function remains focused and substance undiminished. However, the preservation of Essence is not solely for nurturing Tian Zhen; preserving Essence makes Yin solid. The Classics state: Yin forms structure. When Yin is solid, the structure is whole; when Yin is deficient, the structure deteriorates. Deterioration leads to the cessation of entry and exit, and the stopping of ascent and descent; how can solitary Yang Qi not become hyperactive and fly away? Master Dai once said: People suffer diseases due to the fire of emotions, overwork, and sexual desire, which simmer Kidney Water and exhaust Essence and Blood; such cases account for six or seven out of ten. All Five Zang belong to Yin and store Essence; the Kidney is the master of Yin Qi among the Five Zang, thus receiving and storing the Essence of all Zang. Therefore, all diseases of Yin Essence and Blood originate from the Kidney. One must carefully examine the Kidney’s transport and storage functions! Generally, following Zhang Zhongjing’s Ba Wei Wan (Eight-Ingredient Pill with Rehmannia), the Five Flavors enter their respective Zang to benefit their Essence; the pungency of Gui Zhi (Cinnamon Twig) and Fu Zi (Aconite Root) opens the Cou Li (skin and hair pores), delivers fluids, and unblocks Qi pathways, transporting and delivering [the medicine]. Methods for tonifying the Kidney certainly adhere to established rules, yet if Earth’s Yin is deficient, Heaven’s Yang cannot descend; or if Yang is chaotic below, preventing Shao Yin (Kidney/Heart) Qi from storing and collecting; or if Essence is exhausted and accumulated without being transported; or if Yin and Yang within the two Kidneys have inherent biases—all these must be treated after careful assessment.
However, Yuan Qi has roots and shoots within the body, but in the Great Void, it is neither Yin nor Yang. Its root originates from the opening of Heaven and Earth, circulating up, down, front, and back, transforming and moving wherever it reaches; this is what Zhang Zhongjing called the Yuan Zhen Zhen Qi (Original True Qi) of the Five Zang. In the Liver, it undergoes warming transformation, and its Qi ascends; in the Heart, it undergoes heating transformation, and its Qi floats; in the Spleen, it undergoes neutral harmony transformation, and its Qi is fully prepared; in the Lungs, it undergoes cooling transformation, and its Qi descends; in the Kidneys, it undergoes cold transformation, and its Qi stores: just as Heaven moves one Yuan Qi through the four seasons. These shoots are discussed and treated according to the Yuan Zhen of their respective root Zang. If what is transformed by Yuan Qi is insufficient, tonify from the Zang where it is transformed; if what is transformed by Yuan Zhen is excessive, drain contrary to its transformation. Thus, discussing Yuan Qi exclusively in the Spleen and Stomach emphasizes grain and water to nourish Tian Zhen. Master Dai further combined the concept of receiving Essence to complete physical formation, emphasizing the two Kidneys as the source of Yuan Jing, establishing the foundation of life and longevity. Qian Zhongyang (Qian Yi) applied only tonification and no draining to the Kidney, precisely reflecting this intent! Both approaches treat from the root.