凡人之所苦谓之病，所以致此病者谓之因。如同一身热也，有风、有寒、有痰、有食、
有阴
虚火升，有郁怒，忧思、劳怯、虫病，此谓之因。知其因则不得专以寒凉治热病矣。盖热同
而所以致热者不同，则药亦迥异。凡病之因不同，而治各别者尽然，则一病而治法多端矣。
而病又非止一症，必有兼症焉。如身热而腹痛，则腹又为一症，而腹痛之因，又复不同，有
与身热相合者，有与身热各别者。如感寒而身热，其腹亦因寒而痛，此相合者也。如身热为
寒，其腹痛又为伤食，则各别者也。又必审其食为何食，则以何药消之。其立方之法，必切
中二者之病源而后定方，则一药而两病俱安矣。若不问其本病之所因，及兼病之何因，而徒
曰某病以某方治之，其偶中者，则投之或愈；再以治他人，则不但不愈而反增病，必自疑曰
何以治彼效而治此不效？并前此之何以愈？亦不知之，则幸中者甚少，而误治者甚多！终身治
病，而终身不悟，历症愈多而愈惑矣。
经云∶夺血者无汗，夺汗者血。血属阴，是汗多乃亡阴也。故止汗之法，必用凉心敛肺
之药
正治也。惟汗出太甚，则阴气上竭，而肾中龙雷之火随水而上。若以寒凉折之，其火愈炽，
惟用大剂参附，佐以咸降之品如童便、牡蛎之类，冷冻饮料一碗，直达下焦，引其真阳下降，则
龙雷之火反乎其位，而汗随止。此与亡阴之汗，真大相悬绝。故亡阴亡阳，其治法截然，而
转机在顷刻。当阳气之未动也，以阴药止汗。乃阳气之既动也，以阳药止汗；而龙骨、牡蛎
、黄 、五味收涩之药，则两方皆可随宜用之。医者能于亡阴亡阳之交，分其界限，则用药
无误矣。其亡阴亡阳之辨法如何？亡阴之汗，身畏热，手足温，肌热，汗亦热而味咸，口渴
喜凉饮，气粗，脉洪实，此其验也；亡阳之汗，身反恶寒，手足冷，肌凉汗冷，而味淡微粘
，口不渴，而喜热饮，气微，脉浮数而空，此其验也。至于寻常之正汗、热汗、邪汗、自汗
，又不在二者之列。此理知者绝少，即此汗之一端，而聚讼纷纷，毫无定见，误治甚多也。
凡是人体所感受的痛苦称为病，导致这种病的根本原因称为因。同样是全身发热，有的由风邪引起，有的由寒邪引起，有的由痰湿引起，有的由食积引起，有的由阴虚火旺引起，有的由郁怒、忧思、劳损虚怯或寄生虫病引起，这些统称为“因”。明白了致病的原因，就不能单纯用寒凉药物来治疗热证了。因为发热的表现虽然相同，但导致发热的原因不同，所用的药物也就截然不同。凡是疾病的成因不同，治疗方法也各不相同，这就是为什么同一种疾病会有多种治法的原因。
而且，疾病不仅仅表现为单一症状，往往伴有兼症。例如身体发热且腹痛，那么腹痛就是另一个症状，而腹痛的成因又各不相同：有的与身体发热的成因相同，有的则与身体发热的成因不同。比如受寒导致身体发热，腹部也因受寒而疼痛，这是成因相合的情况。如果身体发热是因为受寒，而腹痛是因为伤食，这就是成因各别的情况。此时必须仔细审查是吃了什么食物导致的积滞，然后用相应的药物来消导化积。确立方剂的方法，必须切中这两种病症的病源之后才能确定处方，这样一味药（或一个方剂）就能使两种病都得到安宁。如果不问本病的成因以及兼病的成因，只是笼统地说“某病用某方治疗”，偶尔碰巧有效的，投药后或许痊愈；但如果再用这个方子治疗其他人，不仅不能痊愈，反而会增加病情。这时医生必定会自我怀疑：“为什么治那个人有效，治这个人却无效？”甚至连以前为什么能治好也不清楚。这样侥幸成功的很少，误治的却很多！终身行医治病，却终身不悟其中道理，经历的病例越多，就越感到困惑。
《内经》说：“夺血者无汗，夺汗者无血。”血液属于阴，所以汗出过多就是亡阴。因此，止汗的正确治法，必须使用清心敛肺的药物。但是如果汗出太过严重，导致阴气在上部竭绝，肾中的龙雷之火就会随着水液上冲。如果用寒凉药物去压制它，火势反而会更加炽盛。此时只有使用大剂量的参附汤，配合咸味降逆的药物如童便、牡蛎等，再喝一碗冷冻饮料，直达下焦，引导真阳下降，那么龙雷之火就会回归其本位，汗随之停止。这与亡阴之汗的治疗，真是天壤之别。所以，亡阴和亡阳的治疗方法截然相反，而病情的转机就在顷刻之间。当阳气尚未妄动时，用滋阴药止汗；当阳气已经妄动时，用补阳药止汗；而龙骨、牡蛎、黄芩（注：原文‘黄’疑为黄芩或黄芪，结合语境收涩及清热，此处暂译作相关药材，但在实体提取中保留原文‘黄’）、五味子等收敛固涩的药物，则在两个方剂中都可以酌情使用。医生如果在亡阴和亡阳的界限模糊之际，能够分清界限，用药就不会出错。如何辨别亡阴和亡阳呢？亡阴之汗，身体怕热，手足温暖，肌肤发热，汗也是热的且味道咸，口渴喜欢喝冷饮，呼吸粗重，脉象洪大有力，这是其特征；亡阳之汗，身体反而怕冷，手足冰冷，肌肤凉爽，汗冷且味道淡微粘，口不渴而喜欢喝热饮，气息微弱，脉象浮数而中空，这是其特征。至于平常的正汗、热汗、邪汗、自汗，都不在这两类之中。懂得这个道理的人极少，仅就出汗这一端而言，就争论纷纷，毫无定见，导致误治非常多。
What causes suffering in the human body is termed a disease (Bing, 病), and the root cause leading to this disease is termed the etiology (Yin, 因). For instance, systemic heat (Shen Re, 身热) may arise from wind (Feng, 风), cold (Han, 寒), phlegm-dampness (Tan, 痰), food stagnation (Shi, 食), deficiency fire rising due to Yin deficiency (Yin Xu Huo Sheng, 阴虚火升), emotional depression and anger (Yu Nu, 郁怒), worry and overthinking (You Si, 忧思), consumptive weakness (Lao Qie, 劳怯), or parasitic diseases (Chong Bing, 虫病); these are all referred to as "etiology." Understanding the etiology prevents one from exclusively treating heat syndromes with cold-cooling herbs. Since the manifestation of heat is similar but the underlying causes differ, the medicinal prescriptions must also be radically different. This principle applies universally: when etiologies differ, treatments must vary, resulting in multiple therapeutic approaches for a single disease entity.
Furthermore, a disease is not limited to a single symptom but often presents with concurrent symptoms (Jian Zheng, 兼症). For example, if there is systemic heat accompanied by abdominal pain, abdominal pain constitutes a separate symptom. The etiology of abdominal pain also varies: it may share the same cause as the systemic heat, or it may be distinct. If exposure to cold causes both systemic heat and abdominal pain, the etiologies are combined. However, if systemic heat is caused by cold while abdominal pain results from food injury, the etiologies are distinct. In such cases, one must carefully identify the specific type of food causing stagnation and prescribe appropriate digestive herbs. The formulation of a prescription must precisely target the pathological sources of both conditions before finalizing the formula, thereby ensuring that a single treatment resolves both ailments simultaneously. If one ignores the etiology of the primary disease and the concurrent symptoms, merely stating "disease X is treated with formula Y," occasional success might lead to temporary recovery. However, applying the same formula to others may fail to cure and instead exacerbate the condition. The physician would then doubt themselves, wondering why it worked previously but fails now, without understanding the reason for previous successes. Such lucky coincidences are rare, while misdiagnoses are frequent. One may practice medicine for a lifetime yet remain ignorant, becoming more confused as the number of cases increases.
The *Classic of Internal Medicine* (*Huangdi Neijing*, 黄帝内经) states: "Those who lose blood should not sweat; those who lose sweat should not lose blood." Blood belongs to Yin; therefore, excessive sweating indicates the collapse of Yin (Wang Yin, 亡阴). Thus, the orthodox method for stopping sweat involves using herbs that cool the Heart and astringe the Lung. However, if sweating is excessively severe, Yin Qi may exhaust upwards, causing the Dragon-Lei Fire (Long Lei Zhi Huo, 龙雷之火) within the Kidney to ascend with the fluids. Applying cold-cooling herbs to suppress this fire will only intensify it. Instead, large doses of Shen Fu Tang (Ginseng and Aconite Decoction) should be used, assisted by salty descending agents such as child's urine (Tong Bian, 童便) and Oyster Shell (Muli, 牡蛎). Drinking a bowl of chilled beverage directly reaches the Lower Jiao (Xia Jiao, 下焦), guiding the True Yang (Zhen Yang, 真阳) downward. Consequently, the Dragon-Lei Fire returns to its proper position, and sweating ceases. This approach is vastly different from the treatment of sweat associated with Yin collapse. Therefore, the therapeutic methods for Yin collapse and Yang collapse (Wang Yang, 亡阳) are截然 (jie ran, 截然 - distinct/opposite), and the turning point of the condition occurs in an instant. When Yang Qi has not yet deviated, Yin-nourishing herbs are used to stop sweat; once Yang Qi has deviated, Yang-tonifying herbs are used. Herbs with astringent properties such as Dragon Bone (Long Gu, 龙骨), Oyster Shell (Muli, 牡蛎), Scutellaria (Huang Qin, 黄芩 - inferred from context 'Huang'), and Schisandra (Wu Wei Zi, 五味子) can be appropriately included in either formula. If physicians can distinguish the boundary between Yin and Yang collapse, medication errors will be avoided. How to differentiate between Yin and Yang collapse? Sweat from Yin collapse is characterized by aversion to heat, warm hands and feet, hot skin, hot and salty-tasting sweat, thirst preferring cold drinks, coarse breathing, and a surging and solid pulse. These are the diagnostic signs. Sweat from Yang collapse is characterized by aversion to cold, cold hands and feet, cool skin, cold and faintly sticky/tasteless sweat, no thirst but preference for hot drinks, weak breath, and a floating, rapid, and empty pulse. These are the diagnostic signs. Ordinary normal sweat, heat sweat, pathogenic sweat, and spontaneous sweat do not fall into these two categories. Few people understand this principle. Regarding sweat alone, debates are rampant, lacking definitive views, leading to numerous misdiagnoses.