天有四时春为始。圣人作经。谓之履端。盖履端于始。序则不愆。以时令考之。生气既
至。
大禁
不
倡
中
盛。主万物悉皆殒绝而不见。其为肃杀可知矣。寒物寒药。既禀此化而生。施之于人。非肃
杀
犹
不
草
生
道
一
天
当从权用之。以气平而止。如执而有所偏助。令脏气不平。呜呼。死生之机。捷若影响。殆
不可忽。治寒以温。治热以凉。但中病即止。矫枉则过正也。盖凉药频施。必至于疲 沉冷。
温药频施。必至于烦燥闷热。所贵酌量权度。一毫无过用焉。是为活法。牵牛非神农药也。
本草名医续注云。味苦寒。能除湿利小便。治下注香港脚。此说气味主治俱误矣。何以明之。
凡药用牵牛者。少则动大便。多则泄下如水。乃泻气之药。试取尝之。便得辛辣之味。久而
嚼之。猛烈雄壮。渐渐不绝。非辛而何。续注味苦寒。果安在哉。苦以为湿家泻药。尤不知
其的也。何则能泻气中之湿热。不能除血中之湿热。况湿从下受之。下焦主血。是血中之湿
。宜苦寒之味。今反以辛药泻之。其伤必矣。夫湿者。地之别名。有形者也。若肺先受湿。
则宜用之。或有湿无湿。但伤食或动大便。或有热证。或只常服克化之药。但用牵牛。岂不
误哉。殊不知牵牛辛烈。泻人元气。比之诸辛药尤甚。以辛之雄烈故也。经云。辛泄气。辛
走气。辛泻肺气。肺病者无多食辛。况饮食失节。劳役所伤。是胃气不行。心火乘之。肠胃
受火邪。名曰热中。经云、脾胃主血。当血中泻火。润燥补血。泻胃经之湿热。及胸中热。
是肺受火邪。以黄芩之苦寒抑之。以当归之辛温和血。以生地黄苦寒凉血益血。少加红花之
辛温。以泻血络。以桃仁之辛温。油腻之药。除燥润大便。然犹不可专用。须于补中益气汤
。泻阴火之药内。兼而用之。何则上焦元气。已自虚弱。若反用牵牛大辛辣气味俱阳之药。
以泻水泻气可乎。津液已不足。口燥舌干。而重泻其津液。利其小便。元气伤竭。致阴火愈
甚。今重为备言之。牵牛。感南政热火之化所生者也。血热泻气。差误太甚。若病湿胜。湿
气不得施化。致大小便不通。则宜用之耳。湿去则气周流。所谓五脏有邪更相平也。经云。
一脏未平。以所胜平之。火能平金而泄肺者。此之谓也。近代钱氏泻黄散中独用防风。比之
余药过于两倍者。以防风辛温令于土中泻金不助湿者也。经云。从前来者为实邪。谓子能令
母实。实则泻其子。此之谓以所胜者平之也。古人有云。牵牛不可耽嗜。则脱人元气。经云
。秋不食姜。令人泻气。故夏月食姜不禁。为气正王之时。夏宜以汗散火。令其以汗出越其
热。故秋月则禁之。朱晦庵语录中有戒秋食姜。则夭人天命。戒之深也。姜尚如此。况牵牛
乎
能
在下焦。是血分中气病。不可用辛辣气药。泻上焦太阴之气故也。
仲景尚不敢轻用如此。世医一概用之可乎。
天有四季，以春季为起始。圣人制定经典，称之为“履端”。所谓在开端处遵循正道，秩序就不会有过失。根据时令来考察，当生发之气已经到来时，（若使用）大禁之物，不顺应中盛之理，会导致万物全部凋零灭绝而看不见生机，其肃杀之气可以想见。寒性的食物和寒性的药物，既然禀受这种化育而生，施用于人体，除非从权变通使用，否则应当以气机平和为停止标准。如果固执地有所偏颇助长，导致脏腑之气不平衡，唉！死生的关键，迅速得像影子跟随形体、回声响应原声一样，大概不可以忽视。治疗寒证用温药，治疗热证用凉药，只要中病（药效对症）就立即停止，纠正偏差过了头就会变成新的错误。因为凉性药物频繁施用，必然导致疲乏、沉冷；温性药物频繁施用，必然导致烦躁、燥热、闷热。可贵之处在于斟酌衡量权度，丝毫不让药物过用，这才是灵活的方法。
牵牛子并不是神农氏时代的药物。《本草名医续注》说：味苦寒，能除湿利小便，治疗下注的香港脚（足部肿痛溃烂）。这个说法关于气味和主治都错了。怎么证明呢？凡是药用牵牛子的，少量则推动大便，大量则泻下如水，这是泻气的药物。试着取来品尝，便得到辛辣的味道，久嚼之后，猛烈雄壮，渐渐不绝，这不是辛味又是什么呢？《续注》说味苦寒，究竟在哪里呢？如果说苦味是作为湿家（患湿病者）的泻药，尤其不知道它的真谛。为什么呢？因为它能泻气分中的湿热，不能清除血分中的湿热。况且湿气是从下部感受的，下焦主血，所以血中的湿气，适宜用苦寒的味道。现在反而用辛药来泻它，伤害必定发生。
所谓湿，是地的别名，是有形的物质。如果肺先受到湿气影响，则适宜使用（牵牛）。或者无论有没有湿，只是伤食或推动大便，或者有热证，或者只常服用消导克化的药物，只用牵牛子，难道不是错误吗？殊不知牵牛子辛烈，泻人元气，比其他的辛药更为严重，这是因为其辛味雄烈所致。经书说：辛味泄气，辛味走气，辛味泻肺气。肺病患者不要多吃辛味食物。何况饮食失节，劳役所伤，导致胃气不行，心火乘虚侵袭，肠胃受到火邪，名叫热中。经书说：脾胃主血，应当在血中泻火，润燥补血，泻胃经的湿热，以及胸中的热。这是肺受到火邪，用黄芩的苦寒来抑制它，用当归的辛温来调和血液，用生地黄苦寒来凉血益血，少加红花的辛温，来泻血络，用桃仁的辛温及油腻的药物，来除燥润大便。然而仍然不可以专用这些药，必须在补中益气汤、泻阴火的药物内，兼而使用。为什么呢？上焦元气，本来就已经虚弱，如果反而用牵牛子这样大辛辣、气味俱阳的药物，来泻水泻气，可以吗？津液已经不足，口燥舌干，如果再重泻其津液，利其小便，元气损伤枯竭，导致阴火更加旺盛。现在再次详细陈述。
牵牛子，是感南政热火之气化所生成的。血热而泻气，差错失误太严重了。如果是病湿胜，湿气不得施化，导致大小便不通，则适宜使用它。湿气去除则气周流运行，所谓五脏有邪气更相平衡。经书说：一脏未平，用其所胜之脏来平复它。火能平金而泄肺，说的就是这个道理。近代钱乙的泻黄散中独用防风，比其余药物超过两倍，是因为防风辛温，令其在土中泻金而不助湿。经书说：从前来者为实邪，谓子能令母实，实则泻其子，这就是所说的用所胜者来平复它。古人有话说：牵牛子不可沉迷嗜用，否则会脱失人的元气。经书说：秋天不吃姜，令人泻气。所以夏天吃姜不禁忌，因为此时气正王（旺盛）之时。夏天适宜以汗法发散火邪，令其通过出汗来越出热邪，所以秋天就禁止食用。朱熹语录中有戒止秋天吃姜，则会夭折人的天命，告诫得非常深刻。姜尚且如此，何况牵牛子呢？
（牵牛子）在下焦，是血分中的气病，不可用辛辣气药，因为要泻上焦太阴（肺）之气的原因。张仲景尚且不敢轻易使用如此（猛烈的药），世间的医生一概使用它，可以吗？
Heaven has four seasons, with Spring as the beginning. The Sages established the classics, calling it "Lüduan" (Starting at the correct foundation). This means adhering to the right path at the beginning, so that order will not err. Examining according to seasonal timing: when the Qi of generation has arrived, if one uses substances under the "Great Taboo" without promoting the flourishing of mid-season vitality, all things will perish and vanish, revealing its desolate and killing nature. Cold foods and cold medicines, having been born from this transformation, when applied to humans, should only be used flexibly according to circumstances, stopping when Qi becomes balanced. If one rigidly aids a bias, causing the Zang-Fu Qi to become unbalanced, alas! The mechanism of life and death is swift as shadow following form or echo responding to sound; it must not be neglected. Treat cold with warm, treat heat with cool, but stop once the disease is addressed; correcting deviation beyond measure leads to excess. Frequent use of cool medicines inevitably leads to fatigue and deep cold; frequent use of warm medicines inevitably leads to irritability, dryness, heat, and stifling sensation. The value lies in weighing and measuring, ensuring no overuse whatsoever; this is the living method.
Qian Niu (Pharbitidis Semen) is not an herb from the time of Shennong. The *Bencao Mingyi Zhuxu* states: Bitter and cold, it can remove dampness and promote urination, treating lower-jiao Hong Kong foot (podagra/ulcerative foot swelling). This statement regarding taste, nature, and indications is entirely wrong. How do we know? Whenever Qian Niu is used medicinally, in small doses it moves the bowels; in large doses, it causes watery diarrhea. It is a medicine that drains Qi. Try tasting it, and you will find a pungent flavor; chewing it for a long time reveals a fierce and vigorous quality that persists, which is undoubtedly Pungent. Where, then, is the Bitter and Cold mentioned in the *Zhuxu*? To say Bitter serves as a purgative for dampness patients is especially ignorant of its true nature. Why? Because it can drain Damp-Heat from the Qi level but cannot remove Damp-Heat from the Blood level. Moreover, Dampness is acquired from below; the Lower Jiao governs Blood. Therefore, Dampness in the Blood should be treated with Bitter-Cold flavors. Now, using Pungent drugs to drain it will surely cause injury.
Dampness is another name for Earth; it is tangible. If the Lung first receives Dampness, then [Qian Niu] might be appropriate. Or whether there is Dampness or not, if there is merely food stagnation or need to move the bowels, or if there are Heat syndromes, or if one simply takes digestive-purging drugs regularly, using only Qian Niu—would this not be a mistake? One does not realize that Qian Niu is Pungent and fierce, draining human Yuan Qi (Original Qi), even more so than other Pungent drugs, due to its fierce Pungency. The Classics state: Pungent drains Qi; Pungent travels through Qi; Pungent drains Lung Qi. Those with Lung diseases should not eat much Pungent food. Furthermore, irregular diet and labor injury cause Stomach Qi to fail to circulate; Heart Fire exploits this, invading the intestines and stomach, named "Re Zhong" (Internal Heat). The Classics state: Spleen and Stomach govern Blood; one should drain Fire within the Blood, moisten dryness, nourish Blood, drain Damp-Heat from the Stomach Meridian, and clear Heat in the chest. This addresses Lung affected by Fire Evil. Use Huang Qin (Scutellariae Radix, Scutellaria Root) Bitter-Cold to suppress it; use Dang Gui (Angelicae Sinensis Radix, Chinese Angelica Root) Pungent-Warm to harmonize Blood; use Sheng Di Huang (Rehmanniae Radix, Prepared Rehmannia Root) Bitter-Cold to cool Blood and benefit Blood; add a little Hong Hua (Carthami Flos, Safflower) Pungent-Warm to drain blood collaterals; use Tao Ren (Persicae Semen, Peach Kernel) Pungent-Warm and greasy/oily medicines to remove dryness and moisten the bowels. However, these should not be used exclusively; they must be combined with Bu Zhong Yi Qi Tang (Tonify the Middle and Augment the Qi Decoction) and medicines that drain Yin Fire. Why? Because Upper Jiao Yuan Qi is already weak; if one instead uses Qian Niu, a drug with strong Pungency and Yang-natured taste and qi, to drain Water and Qi, is this advisable? Jin Ye (Body Fluids) are already insufficient, with dry mouth and tongue; heavily draining fluids again via diuresis will injure and exhaust Yuan Qi, causing Yin Fire to become even more severe. I now elaborate further.
Qian Niu is generated by sensing the transformation of South Polarity Fire-Heat. Draining Qi due to Blood Heat is a grave error. It is only appropriate if Dampness is excessive, preventing Dampness from transforming, leading to obstruction of urination and defecation. Once Dampness is removed, Qi circulates freely, known as the mutual balancing of the Five Zang organs when afflicted by evil. The Classics state: When one Zang is unbalanced, balance it with what controls it. Fire controls Metal and drains the Lung; this is what is meant. In modern times, Qian Yi's Xie Huang San (Drain Yellow Powder) uses only Fang Feng (Saposhnikoviae Radix, Divaricate Saposhnikovia Root), in double the amount of other herbs, because Fang Feng is Pungent-Warm, allowing it to drain Metal within Earth without assisting Dampness. The Classics state: What comes from the preceding element is Excess Evil, meaning the Child can make the Mother full; when Full, drain the Child. This is called balancing with what controls it. Ancients said: Do not indulge in Qian Niu, or it will deplete human Yuan Qi. The Classics state: Do not eat Ginger in Autumn, as it drains Qi. Thus, eating Ginger in Summer is not prohibited, as Qi is prosperous at that time. Summer suits dispersing Fire via sweating, allowing Heat to escape through perspiration; hence, it is forbidden in Autumn. Zhu Xi's recorded sayings warn against eating Ginger in Autumn, stating it shortens lifespan, warning deeply. If Ginger is thus restricted, how much more so Qian Niu?
[Regarding Qian Niu] in the Lower Jiao, it is a Qi disorder within the Blood level; one must not use Pungent-Aromatic Qi-draining drugs, because the intention is to drain Upper Jiao Tai Yin (Lung) Qi. Even Zhang Zhongjing dared not use such [potent drugs] lightly; how can physicians today use them indiscriminately?