小柴胡去人参、甘草，加枳实、芍药、大黄，乃少阳、阳明合治之方也。
柴胡（半斤） 半夏（半升，洗） 黄芩（三两） 芍药（三两） 生姜（五两，切） 枳实（四枚，炙） 大枣
（十二，擘） 上七味，以水一斗二升，煮取六升，去渣，再煎取三升，温服一升，日三服。
此方本有大黄二两。王叔和云∶若不加大黄，恐不为大柴胡也。
太阳病，过经十余日，反二、三下之，一误再误。后四、五日，柴胡证仍在者，如寒热呕逆之类。先与小
柴胡汤。呕不止，心下急，郁郁微烦者，犹有里症。为未解也，与大柴胡汤下之则愈。前虽已下，非下法也，
以大柴胡两解之。
伤寒十余日，热结在里，此大黄之对症。复往来寒热者，此柴胡之对症。与大柴胡汤。
伤寒发热，汗出不解，当用柴胡。心中痞硬，呕吐而下利者。邪内陷，故用枳实、半夏、大黄。大柴胡
汤主之。
伤寒后 后者，过经之后，诸症渐轻，而未全愈也。脉沉，沉者内实也，沉为在里。下解之，宜大柴胡汤。
此小柴胡与桂枝汤并为一方，乃太阳、少阳合病之方。
柴胡（四两） 黄芩 人参 桂枝 芍药 生姜（切，各一两半） 半夏（二合半） 甘草（一两，炙） 大枣
（六枚） 上九味，水七升，煮取三升，去渣，温服一升。
伤寒六、七日，发热微恶寒，肢节疼烦，以上太阳症。微呕、心下支结，以上少阳症。外证未去者、
太阳症为外症。柴胡桂枝汤主之。
发汗多，亡阳 语者，此亡阳之轻者也。不可下，勿误以为有燥屎之 语，故以为戒。与柴胡桂枝汤和
其营卫，以通津液，后自愈。桂枝汤，和营卫；柴胡汤，通津液，深着二汤合用之功效，而阳亡可复。
Xiao Chai Hu Tang (Minor Bupleurum Decoction) with Ren Shen (Ginseng Radix) and Gan Cao (Licorice Root) removed, plus Zhi Shi (Immature Bitter Orange Fruit), Shao Yao (Peony Root), and Da Huang (Rhubarb Rhizome), is a formula for treating the combined disease of Shaoyang (Lesser Yang) and Yangming (Yang Brightness).
Chai Hu (Bupleuri Radix, half jin), Ban Xia (Pinelliae Tuber, half sheng, washed), Huang Qin (Scutellariae Radix, three liang), Shao Yao (Paeoniae Radix, three liang), Sheng Jiang (Zingiberis Rhizoma Recens, five liang, sliced), Zhi Shi (Aurantii Fructus Immaturus, four pieces, roasted), Da Zao (Jujubae Fructus, twelve pieces, torn open). The above seven ingredients are boiled in ten dou two sheng of water, reduced to six sheng, filtered to remove dregs, and then boiled again to obtain three sheng. Take one sheng warm, three times a day.
This formula originally contains two liang of Da Huang. Wang Shuhe said: "If Da Huang is not added, it cannot be called Da Chai Hu Tang."
In Taiyang disease (disease of the Taiyang/Supreme Yang channel), after more than ten days, if purgative methods were incorrectly applied two or three times, it constitutes a double error. After four or five days, if the Chai Hu syndrome (main symptoms of Shaoyang disease) remains, such as alternating chills and fever, vomiting, and regurgitation, first administer Xiao Chai Hu Tang. If vomiting persists, there is urgency and fullness in the epigastrium, and slight depression and irritability, indicating interior syndromes (pathology located in the zang-fu organs). This shows the pathogen has not resolved; administer Da Chai Hu Tang (Major Bupleurum Decoction) to purge, and the patient will recover. Although purgation was previously attempted, it was not the correct method; now use Da Chai Hu Tang to resolve both exterior and interior simultaneously.
In Shanghan (Cold Damage/exterior febrile diseases), after more than ten days, heat is consolidated internally, which corresponds to the indication for Da Huang. If there are also alternating chills and fever, this corresponds to the indication for Chai Hu. Administer Da Chai Hu Tang.
In Shanghan, fever persists despite sweating, requiring the use of Chai Hu formulas. If there is epigastric stuffiness and hardness, vomiting, and diarrhea, this indicates the pathogen has sunk inward; therefore, use Zhi Shi, Ban Xia, and Da Huang. Treat with Da Chai Hu Tang.
After Shanghan (referring to the period after the disease has passed through its stages, where symptoms gradually lighten but have not fully resolved). The pulse is Chen (deep); a deep pulse indicates internal excess and pathology located in the interior. Apply purgation to resolve it; Da Chai Hu Tang is appropriate.
This combines Xiao Chai Hu Tang with Gui Zhi Tang (Cinnamon Twig Decoction) into one formula, serving as a treatment for the combined disease of Taiyang and Shaoyang.
Chai Hu (Bupleuri Radix, four liang), Huang Qin (Scutellariae Radix), Ren Shen (Ginseng Radix), Gui Zhi (Cinnamomi Ramulus), Shao Yao (Paeoniae Radix), Sheng Jiang (Zingiberis Rhizoma Recens, sliced, each one and a half liang), Ban Xia (Pinelliae Tuber, two he and a half), Gan Cao (Licorice Root, one liang, roasted), Da Zao (Jujubae Fructus, six pieces). The above nine ingredients are boiled in seven sheng of water, reduced to three sheng, filtered to remove dregs, and taken one sheng warm.
In Shanghan, after six or seven days, with slight fever and aversion to cold, pain and irritability in the limbs and joints, these are Taiyang symptoms. Slight vomiting and subcostal fullness/support are Shaoyang symptoms. When exterior signs remain (Taiyang disease is an exterior syndrome), treat with Chai Hu Gui Zhi Tang (Bupleurum and Cinnamon Twig Decoction).
Excessive sweating leads to Wang Yang (collapse of Yang qi) accompanied by Chan Yu (delirious speech). This is a mild case of Yang collapse. Do not use purgatives; do not mistakenly attribute the delirium to dry feces accumulation, thus serving as a warning. Administer Chai Hu Gui Zhi Tang to harmonize Ying and Wei (nutritive and defensive qi systems) and promote the flow of Jin Ye (body fluids), after which the condition will heal spontaneously. Gui Zhi Tang harmonizes Ying and Wei; Chai Hu Tang promotes the flow of Jin Ye. This deeply illustrates the efficacy of combining these two decoctions, allowing collapsed Yang qi to be restored.