柴胡，味苦，气平，微寒。气味俱轻，升而不降，阳中阴也。无毒。入手足少阳、厥阴
之四
经。泻肝胆之邪，去心下痞闷，解痰结，除烦热，尤治疮疡，散诸经血凝气聚，止偏头风，
胸胁刺痛，通达表里邪气，善解潮热。伤寒门中必须之药，不独疟症、郁症之要剂也。妇人
胎
产前后，亦宜用之。目病用之亦良，但可为佐使，而不可为君臣。盖柴胡入于表里之间，自
能
通达经络，故可为佐使，而性又轻清微寒，所到之处，春风和气，善于解纷，所以用之，无
不宜也。然世人正因其用无不宜，无论可用不可用，动即用之。如阴虚痨瘵之类，亦终日煎
服
，耗散真元，内热更炽，全然不悟，不重可悲乎。夫柴胡只可解郁热之气，而不可释骨髓之
炎也，能入于里以散邪，不能入于里以补正，能提气以升于阳。使参、 、归、术，共健脾
而开胃，不能生津以降于阴；使麦冬、丹皮，同益肺以滋肾，能入于血室之中以去热，不能
入于命门之内以去寒。无奈世人妄用柴胡以杀人也，余所以探辨之耳。（〔批〕柴胡散半表
半里之邪，开手即宜用之，远公阐发独精，斟酌尽详。）
或问柴胡不可用之以治阴虚之人是矣，然古人往往杂之青蒿、地骨皮、丹皮、麦冬之内，
每
服退热者，又谓之何？曰∶此阴虚而未甚者也。夫阴虚而火初起者，何妨少用柴胡，引诸补
阴之药，直入于肝、肾之间，转能泻火之速。所恶者，重加柴胡，而又久用不止耳。用药贵
通权达变，岂可拘泥之哉。
又问柴胡既能提气，能补脾而开胃，何以亦有用之而气上冲者，何故？此正见柴胡之不
可妄
用也。夫用柴胡提气而反甚者，必气病之有余者也。气之有余，必血之不足也，而血之不足
也，必阴之甚亏也。水不足以制火，而反助气以升阳，则阴愈消亡，而火愈上达，气安得而
不上冲乎。故用柴胡以提气，必气虚而下陷者始可。至于阴虚火动之人，火正炎上，又加柴
胡以升提之，火愈上腾，而水益下走，不死何待乎？此阴虚火动，断不可用柴胡，不更可信
哉。（〔批〕柴胡提气，止宜提阳气之虚，不宜提阴火之旺，不可不知。）
或问柴胡乃半表半里之药，故用之以治肝经之邪最效，然而肝经乃阴脏也，邪入于肝，
已入
于里矣，又何半表半里之是云，乃往往用柴胡而奏效如神者，何也？夫肝经与胆经为表里，
邪入于肝，未有不入于胆者，或邪从胆而入于肝，或邪已入肝，而尚留于胆，彼此正相望而
相通也。柴胡乃散肝邪，而亦散胆邪之药，故入于肝者半，而入于胆者亦半也。所以治肝而
胆之邪出，治胆而肝之邪亦出也。
或问柴胡既是半表半里之药，邪入于里，用柴胡可引之以出于表，则病必轻；邪入于表，
亦用柴胡，倘引之以入于里，不病增乎？不知柴胡乃调和之
药，非引经之味也。邪入于内者，能和之而外出，岂邪入于内者，反和之而内入乎。此伤寒
汗、吐、下之病，仲景夫子所以每用柴胡，以和解于半表半里之间，使反危而为安，拨乱而
为治也。
又问柴胡既是调和之药，用之于郁症者固宜，然有时解郁，而反动火，又是何故？此必
妇女
郁于怀抱，而又欲得男子，而不可得者也。论妇女思男子而不可得之脉，肝脉必大而弦出于
寸口。然其怀抱既郁，未用柴胡之前，肝脉必涩而有力，一服柴胡，而涩脉必变为大而且弦
矣。郁开而火炽，非柴胡之过，正柴胡之功，仍用柴胡，而多加白芍、山栀，则火且随之而
即散矣。
或问柴胡为伤寒要药，何子不分别言之？曰∶伤寒门中，柴胡之症甚多，何条宜先言，
何条
宜略言乎。虽然柴胡之症虽多，而其要在寒热之往来，邪居于半表半里之言尽之矣，用柴胡
而顾半表半里也，又何误用哉。（〔批〕伤寒用柴胡之症虽多，数言已足包括。）
或问柴胡开郁，凡男子有郁，亦可用之乎？盖一言郁，则男妇尽在其中矣，岂治男一法，而
治女又一法乎。世人治郁，多用香附，谁知柴胡开郁，更易于香附也。
或问柴胡本散风之味，何散药偏能益人，此予之未解也。盖克中不克，克即是生也。柴
胡入
肝，而性专克木。何以克木而反能生木？盖肝属木，最喜者水也，其次则喜风。然风之寒者
，又其所畏，木遇寒风则黄落，叶既凋零，而木之根必然下生而克土矣。土一受伤，而胃气
即不能开而人病，似乎肝之不喜风也，谁知肝不喜寒风，而喜温风也。木一遇温风，则萌芽
即生，枝叶扶疏，而下不生根，又何至克土乎。土不受伤，而胃气辄开，人病顿愈。柴胡，
，风药中之温风也，肝得之而解郁，竟不知抑滞之气何以消释也，故忘其性之相制，转若其
气之相宜。克既不克，非克即所以生之乎。克即是生，克非真克，生乃是克，生实非生。全
生于克之中，制克于生之外，是以反得其生之之益，而去其克之之损也。
或疑柴胡用之于补中益气汤，实能提气，何以舍补中益气汤用之，即不见有功，意者气
得补
而自升，无藉于柴胡耶？曰∶柴胡提气，必须于补气之药提之，始易见功，舍补气之药，实
难奏效。盖升提之力，得补更大，非柴胡之不提气也。
或疑柴胡用之补中益气汤中，为千古补气方之冠，然吾以为柴胡不过用之升提气之下陷
耳，
胡足奇。此真不知补中益气汤之妙也。补中益气汤之妙，全在用柴胡，不可与升麻并论也。
盖气虚下陷，未有不气郁者也。惟郁故其气不扬，气不扬，而气乃下陷，徒用参、归、 、
术以补气，而气郁何以舒发乎。即有升麻以提之，而脾胃之气，又因肝气之郁来克，何能升
哉。得柴胡同用以舒肝，而肝不克土，则土气易于升腾。方中又有甘草、陈皮，以调和于胸
膈之间，则补更有力，所以奏功如神也。是柴胡实有奇功，而非提气之下陷一语可了。使柴
胡止提气之下陷，何风药不可提气，而东垣先生必用柴胡，以佐升麻之不及耶。夫东垣先生
一生学问，全在此方，为后世首推，盖不知几经踌度精思，而后得之也，岂漫然哉。（〔批
〕阐发补中益气之妙，□东垣自己亦不过□□。）
或问大、小柴胡汤，俱用柴胡，何以有大小之分，岂以轻重分大小乎？不知柴胡调和于
半表
半里，原不必分大小也，而仲景张夫子分之者，以大柴胡汤中有攻下之药，故以大别之。实
慎方之意，教人宜善用柴胡也，于柴胡何豫哉。
柴胡，味苦，气平，微寒。气味都轻清，主升而不降，属于阳中阴的范畴。无毒。归入手少阳胆经、足少阳胆经、手厥阴心包经、足厥阴肝经这四条经脉。能泻除肝胆的邪气，消除心下（胃脘部）的痞闷感，化解痰结，清除烦热，尤其擅长治疗疮疡，消散各条经络中的血凝气聚，止偏头痛，缓解胸胁部的刺痛，通达表里之间的邪气，善于解除潮热。它是伤寒病门类中必须使用的药物，不仅仅是治疗疟疾、郁证的重要药剂。妇女在怀孕及产后前后，也适宜使用它。眼部疾病使用它也效果良好，但只能作为佐使药，而不能作为君臣药。因为柴胡进入表里之间，自然能够通达经络，所以可以作为佐使药；而且它的性质轻清微寒，所到达的地方，如同春风和气一般，善于化解纷争，所以使用它，没有不适宜的。然而世人正是因为它使用无不宜，无论是否适用，动不动就使用它。比如阴虚劳瘵之类的病症，也整天煎服，耗散真元，导致内热更加炽盛，完全不明白其中的道理，这难道不可悲吗？柴胡只能解郁热之气，而不能消除骨髓里的炎症；能进入体内以疏散邪气，不能进入体内以补益正气；能提气使其升于阳分。如果配合人参、白术、当归、白术，共同健脾开胃，不能生津液以降于阴分；如果配合麦冬、丹皮，共同益肺滋肾，能进入血室之中以去除热邪，不能进入命门之内以去除寒邪。无奈世人滥用柴胡来杀人，所以我特意探究辨析它。
有人问：柴胡不可用来治疗阴虚之人，这是对的。但是古人往往把它混杂在青蒿、地骨皮、丹皮、麦冬等药物中服用，每服都能退热，这又怎么说呢？回答说：这是阴虚程度还不严重的情况。如果是阴虚而火刚开始起的时候，不妨少量使用柴胡，引导各种补阴的药物，直接深入肝、肾之间，反而能更快地泻火。令人厌恶的是，大量加入柴胡，并且长期服用不停止罢了。用药贵在通权达变，怎么能拘泥不变呢？
又问：柴胡既然能提气，能补脾开胃，为什么也有用了之后气向上冲的情况，这是什么原因？这正是显示柴胡不可滥用的地方。使用柴胡提气反而加重的，一定是气病有余的人。气有余，必然是血不足；血不足，必然是阴严重亏损。水不足以制约火，反而助长气以升发阳气，那么阴液更加消亡，火气更加上达，气怎么能不上冲呢？所以使用柴胡来提气，必须是气虚而下陷的人才可以。至于阴虚火动的人，火正炎上，再加柴胡来升提，火气更加上腾，而水液益向下走，不死还等什么？这说明阴虚火动，绝对不可用柴胡，不是更可信吗？
有人问：柴胡是半表半里的药物，所以用它治疗肝经的邪气最见效。然而肝经是阴脏，邪气进入肝经，已经入里了，为什么说它是半表半里呢？为什么往往用柴胡而奏效如神呢？回答：肝经与胆经互为表里，邪气进入肝经，没有不进入胆经的；或者邪气从胆经进入肝经，或者邪气已经进入肝经，而还留在胆经，彼此正相望而相通。柴胡是疏散肝经邪气，也是疏散胆经邪气的药物，所以作用于肝经占一半，作用于胆经也占一半。所以治疗肝经，胆经的邪气也会出来；治疗胆经，肝经的邪气也会出来。
有人问：柴胡既然是半表半里的药物，邪气入里，用柴胡可以引导它出于体表，那么病情一定会减轻；邪气入表，也用柴胡，倘若引导它进入体内，不是病情加重吗？不知道柴胡是调和的药物，不是引经的药味。邪气进入内部，能和之而外出，难道邪气进入内部，反而和之而内入吗？这是伤寒汗、吐、下法治疗后的病证，张仲景先生所以经常使用柴胡，在半表半里之间进行和解，使危局转为平安，拨乱反正。
又问：柴胡既然是调和的药物，用于郁证固然适宜，但有时解郁，反而动火，又是什么缘故？这一定是妇女胸怀郁结，而又想要得到男子，却得不到的情况。论述妇女思念男子而不得的脉象，肝脉必定大而弦，出现在寸口。然而其怀抱既已郁结，在使用柴胡之前，肝脉必定涩而有力，一服柴胡，涩脉必定变为大而且弦。郁结打开而火势炽盛，不是柴胡的过错，正是柴胡的功效，仍然使用柴胡，而多加白芍、山栀，那么火气就会随之立即消散。
有人问：柴胡是伤寒的要药，为什么您不分别说明？回答说：伤寒门类中，柴胡的症候很多，哪一条应该先说，哪一条应该略说呢？虽然柴胡的症候虽多，但其关键在于寒热往来，邪气居于半表半里，这句话已经概括尽了。使用柴胡顾及半表半里，又怎么会误用呢？
有人问：柴胡开郁，凡是男子有郁结，也可以使用吗？大概一说“郁”，男女都在其中了，难道治男是一法，治女又是另一法吗？世人治疗郁结，多用香附，谁知道柴胡开郁，比香附更容易见效。
有人问：柴胡本是散风的药味，为什么散药偏偏能益人，这是我未解之处。大概克制之中不克制，克制就是生发。柴胡入肝，性质专门克制木。为什么克制木反而能生木？因为肝属木，最喜欢的是水，其次喜欢风。然而寒冷的风，又是它所畏惧的，树木遇到寒风就会枯黄凋落，叶子既然凋零，树的根必然向下生长而克制土。土一旦受伤，胃气就不能开启而人生病，似乎肝不喜欢风，谁知肝不喜欢寒风，而喜欢温风。树木一遇到温风，萌芽就产生，枝叶繁茂，而下面不生根，又何至克制土呢？土不受伤害，胃气就开启，人的病立刻痊愈。柴胡，是风药中的温风，肝得到它而解郁，竟然不知道滞抑的气是如何消释的，所以忘记了性的相制，转而觉得气的相宜。克制既然不是真正的克制，不是克制不就是生发吗？克制就是生发，克制并非真克制，生发乃是克制，生发实在不是生发。全生于克制之中，制克于生发之外，所以反而得到生发的益处，而去掉克制的损害。
有人怀疑柴胡用在补中益气汤中，确实能提气，为什么舍弃补中益气汤单独使用它，就见不到功效，意思是气得到补益而自己上升，不需要借助柴胡吗？回答说：柴胡提气，必须在补气药的基础上提气，才容易见到功效，舍弃补气药，实在难以奏效。因为升提的力量，得到补益后更大，不是柴胡不提气。
有人怀疑柴胡用在补中益气汤中，是千古补气方的冠军，但我认为柴胡不过是用来升提下陷之气罢了，有什么奇特的。这真是不知道补中益气汤的妙处。补中益气汤的妙处，全在于使用柴胡，不能与升麻并列讨论。因为气虚下陷，没有不伴有气郁的。正因为有郁结，所以气不扬，气不扬，气才下陷，只用参、归、术来补气，气郁如何舒展发散呢？即使有升麻来提举，脾胃之气，又因肝气之郁来克制，怎么能升举呢？得到柴胡共同用来舒肝，肝就不克制脾土，那么土气易于升腾。方中又有甘草、陈皮，在胸膈之间进行调和，那么补益更有力量，所以奏效如神。因此柴胡确实有奇功，而不是“提气之下陷”一句话可以概括的。假如柴胡只提下陷之气，什么风药不可以提气，而李东垣先生一定要用柴胡，来辅助升麻的不足呢？李东垣先生一生的学问，全在这个方子，为后世首推，大概不知经过多少次斟酌精思，而后得到的，难道是随意的吗？
有人问：大、小柴胡汤，都用柴胡，为什么有大小的区别，难道是以轻重分大小吗？不知道柴胡调和于半表半里，原本不必分大小。而张仲景先生区分它们，是因为大柴胡汤中有攻下的药物，所以用“大”来区别。这是谨慎处方的意思，教导人应该善用柴胡，这与柴胡本身有什么关系呢？
Chai Hu (Bupleuri Radix), bitter in taste, neutral in qi, slightly cold. Its aroma and flavor are both light; it ascends but does not descend, belonging to the category of "Yin within Yang." It is non-toxic. It enters the four meridians of Hand-Shaoyang (Sanjiao/Gallbladder channel connection contextually implies Shaoyang channels), Foot-Shaoyang (Gallbladder meridian), Hand-Jueyin (Pericardium meridian), and Foot-Jueyin (Liver meridian). It drains pathogenic factors from the Liver and Gallbladder, removes epigastric fullness and stuffiness, resolves phlegm nodules, eliminates irritability and heat, and is especially effective for treating sores and ulcers. It disperses blood stasis and Qi stagnation in various meridians, stops hemicephalic migraine, relieves stabbing pain in the chest and hypochondrium, unblocks pathogenic factors between the exterior and interior, and is adept at resolving tidal fever. It is an indispensable herb in the treatment of Shanghan (Cold Damage) diseases, serving not only as a key agent for malaria and Yu syndrome (Depression/Stagnation syndrome). It is also suitable for women before and after pregnancy and childbirth. It is beneficial for eye diseases, but can only serve as an assistant or guide herb (Zuo Shi), not as a sovereign or minister herb. Since Chai Hu enters the space between the exterior and interior, it naturally unblocks the collaterals, thus qualifying it as an assistant or guide herb. Furthermore, its nature is light, clear, and slightly cold; where it reaches, it acts like a gentle spring breeze, adept at resolving conflicts. Therefore, its use is universally appropriate. However, people, precisely because of its universal appropriateness, use it indiscriminately regardless of suitability. For instance, in cases of Yin deficiency with consumptive disease (Lao Zhai), it is decocted and taken daily, depleting true Yuan Qi and exacerbating internal heat, yet users remain oblivious. Is this not truly pitiable? Chai Hu can only resolve Qi stagnation with heat, but cannot eliminate inflammation in the bone marrow; it can enter the interior to disperse pathogens, but cannot enter the interior to tonify healthy Qi; it can lift Qi to ascend to the Yang level. If combined with Ren Shen (Ginseng Root), Bai Zhu (Atractylodis Macrocephalae Rhizoma), Dang Gui (Angelicae Sinensis Radix), and Bai Zhu (Atractylodis Macrocephalae Rhizoma - *Note: Text repeats Bai Zhu or implies Fu Ling/Bai Zhu context, usually Si Jun Zi Tang components*), they jointly strengthen the Spleen and open the Stomach, but cannot generate body fluids to descend to the Yin level; if combined with Mai Dong (Ophiopogonis Tuber) and Dan Pi (Moutan Cortex), they jointly benefit the Lung and nourish the Kidney, entering the Blood Chamber to remove heat, but cannot enter the Ming Men (Gate of Life) to remove cold. Regrettably, people misuse Chai Hu to cause death, which is why I have explored and analyzed it.
One asks: It is correct that Chai Hu should not be used to treat individuals with Yin deficiency. However, ancient practitioners often mixed it with Qing Hao (Artemisiae Annuae Herba), Di Gu Pi (Lycii Cortex), Dan Pi (Moutan Cortex), and Mai Dong (Ophiopogonis Tuber), and each dose reduced fever. How should this be explained? The answer is: This applies to cases where Yin deficiency is not severe. In cases where Yin deficiency leads to initial fire flare-up, it is permissible to use a small amount of Chai Hu to guide various Yin-nourishing herbs directly into the Liver and Kidneys, thereby accelerating the draining of fire. What is objectionable is adding heavy doses of Chai Hu and using it continuously for a long time. Medication requires flexibility and adaptation; one cannot be rigid.
Another asks: Since Chai Hu can lift Qi and strengthen the Spleen to open the Stomach, why does it sometimes cause Qi to rush upward when used? This demonstrates that Chai Hu must not be used recklessly. When Chai Hu is used to lift Qi but symptoms worsen, it indicates an excess condition of Qi. Excess Qi implies insufficiency of Blood; insufficiency of Blood implies severe depletion of Yin. When Water (Kidney Yin) is insufficient to control Fire, it fails to restrain Qi from ascending Yang, leading to further consumption of Yin and rising Fire. How can Qi not rush upward? Therefore, Chai Hu should only be used to lift Qi in cases of Qi deficiency with sinking. For individuals with Yin deficiency and moving Fire, where Fire is already flaming upward, adding Chai Hu to lift further causes Fire to rise higher while Water sinks lower. Death is inevitable. Thus, for Yin deficiency with moving Fire, Chai Hu is absolutely contraindicated, which is even more convincing.
One asks: Chai Hu is a herb for the half-exterior, half-interior stage, making it most effective for pathogenic factors in the Liver meridian. However, the Liver meridian is a Yin organ; once pathogens enter the Liver, they are already in the interior. Why is it described as half-exterior, half-interior? Why does Chai Hu often work miraculously? The answer is: The Liver and Gallbladder meridians are exterior-interior pairs. Pathogens entering the Liver invariably enter the Gallbladder. Whether pathogens move from Gallbladder to Liver, or remain in the Gallbladder after entering the Liver, they interact and connect. Chai Hu disperses pathogens in both the Liver and Gallbladder meridians equally. Thus, treating the Liver clears Gallbladder pathogens, and treating the Gallbladder clears Liver pathogens.
One asks: If Chai Hu is for the half-exterior, half-interior stage, using it to draw interior pathogens to the exterior should lighten the disease. But if pathogens are in the exterior and Chai Hu draws them inward, wouldn't the disease worsen? One must understand that Chai Hu is a harmonizing herb, not a guiding herb for specific meridians. If it can harmonize interior pathogens to exit outward, it will not harmonize them to enter deeper. This explains why Zhang Zhongjing frequently used Chai Hu in Shanghan conditions following sweating, vomiting, or purging therapies, to harmonize at the half-exterior, half-interior level, turning danger into safety and chaos into order.
Another asks: If Chai Hu is a harmonizing herb, it is suitable for Yu syndrome (Stagnation). Yet sometimes it resolves stagnation but provokes fire. Why? This typically occurs in women who are emotionally stifled and desire a man they cannot obtain. In such cases, the Liver pulse is large and wiry at the Cun position. Before using Chai Hu, due to emotional depression, the Liver pulse is choppy yet forceful. After one dose of Chai Hu, the choppy pulse transforms into large and wiry. The stagnation opens, and fire flares up. This is not Chai Hu's fault, but its efficacy. Continuing to use Chai Hu while adding Bai Shao (Paeoniae Radix Alba) and Shan Zhi (Gardeniae Fructus) will dissipate the fire immediately.
One asks: Chai Hu is a key herb for Shanghan. Why do you not distinguish its applications specifically? The answer is: There are many indications for Chai Hu in Shanghan. Which should be stated first and which briefly? Although there are many indications, the core lies in alternating chills and fever, indicating pathogens residing in the half-exterior, half-interior. As long as one considers the half-exterior, half-interior aspect when using Chai Hu, misuse is avoided.
One asks: Chai Hu resolves stagnation. Can men with stagnation also use it? The term "stagnation" encompasses both men and women. Are the treatments for men and women different? People often use Xiang Fu (Cyperi Rhizoma) for stagnation, unaware that Chai Hu resolves stagnation more effectively than Xiang Fu.
One asks: Chai Hu is a wind-dispersing herb. Why do dispersing herbs benefit the body? This is my point of confusion. Essentially, "controlling" is also "generating." Chai Hu enters the Liver and specifically controls Wood. Why does controlling Wood generate Wood? The Liver belongs to Wood, preferring Water primarily, and Wind secondarily. However, it fears cold wind; trees yellow and shed leaves in cold wind, causing roots to grow downward and control Earth. If Earth is damaged, Stomach Qi cannot open, and illness arises, suggesting the Liver dislikes wind. Actually, the Liver dislikes cold wind but likes warm wind. Warm wind causes buds to sprout and branches to flourish without roots digging deep into Earth. Earth remains undamaged, Stomach Qi opens, and illness heals. Chai Hu is the "warm wind" among wind herbs. The Liver uses it to resolve stagnation, unknowingly dissolving stagnant Qi. Thus, one forgets the mutual restriction of natures and perceives the harmony of Qi. Control is not true control; control is generation. Generation is control; generation is not mere generation. True generation lies within control, and control exists outside generation. Thus, one gains the benefits of generation and avoids the harms of control.
One doubts: Chai Hu lifts Qi in Bu Zhong Yi Qi Tang (Tonify the Middle and Augment the Qi Decoction). Why does it show no effect when used alone, excluding the decoction? Does Qi rise on its own when tonified, needing no Chai Hu? The answer is: Chai Hu lifts Qi effectively only when combined with Qi-tonifying herbs. Without them, it is hard to achieve results. The lifting power is greater with tonification; it is not that Chai Hu fails to lift Qi.
One doubts: Chai Hu in Bu Zhong Yi Qi Tang is the crown of ancient Qi-tonifying formulas. I believe Chai Hu merely lifts sinking Qi, which is not remarkable. This shows ignorance of the formula's subtlety. The brilliance of Bu Zhong Yi Qi Tang lies entirely in Chai Hu, distinct from Sheng Ma (Cimicifugae Rhizoma). Qi deficiency with sinking always involves Qi stagnation. Due to stagnation, Qi does not manifest, leading to sinking. Using only Ren Shen, Dang Gui, Bai Zhu, etc., to tonify Qi does not resolve stagnation. Even with Sheng Ma to lift, Spleen-Stomach Qi is constrained by Liver Wood overacting on Earth. Chai Hu soothes the Liver, preventing Wood from controlling Earth, allowing Earth Qi to ascend easily. Gan Cao (Licorice Root) and Chen Pi (Citri Reticulatae Pericarpium) harmonize the chest and diaphragm, enhancing tonification. Thus, Chai Hu has miraculous effects, beyond just lifting sinking Qi. If Chai Hu only lifted sinking Qi, any wind herb could do so. Why did Li Dongyuan insist on Chai Hu to assist Sheng Ma? Li Dongyuan's life work centers on this formula, highly praised by later generations, resulting from profound deliberation, not random choice.
One asks: Both Da Chai Hu Tang (Major Bupleuri Decoction) and Xiao Chai Hu Tang (Minor Bupleuri Decoction) use Chai Hu. Why the distinction of "Large" and "Small"? Is it based on dosage weight? Chai Hu harmonizes the half-exterior, half-interior and need not be distinguished by size. Zhang Zhongjing distinguished them because Da Chai Hu Tang contains purgative herbs, hence "Large." This reflects cautious prescribing, teaching proper use of Chai Hu, unrelated to Chai Hu itself.