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Chaihu (Bupleuri Radix): It has a slightly bitter taste and a neutral nature. Endowed with the ascending and generating qi of Shaoyang (Lesser Yang), it is the principal herb for the Foot-Shaoyang Gallbladder Meridian, while also treating disorders of the Foot-Jueyin Liver Meridian. When Liver Qi is not flowing smoothly, this herb can soothe it; when Gallbladder Fire is extremely blazing, this herb can disperse it; regarding external contraction pathogens located in the Shaoyang stage, it can further assist the pivot mechanism to facilitate the emergence of pathogens through the diaphragm upwards. Therefore, *Shennong Bencao Jing* (Divine Farmer's Materia Medica) states that it mainly treats chills and fever; here, "chills and fever" refer to the external pathogens affecting the Shaoyang meridian. It also states that it treats accumulated Qi in the heart, abdomen, intestines, and stomach, as well as food stagnation. This is indeed because according to the theory of Five Elements, Wood can loosen Earth. Chaihu excels at reaching the Wood Qi of Shaoyang; thus, the Qi of Shaoyang naturally unblocks the depression of Stomach Earth, and the accumulated Qi and food stagnation are naturally digested.

*Shennong Bencao Jing* records that Chaihu treats chills and fever, and Shanzhuyu (Corni Fructus) also treats chills and fever. The chills and fever treated by Chaihu are caused by external pathogens of the Shaoyang meridian, such as Shanghan (Cold Damage) or malaria, so it is appropriate to use Chaihu for harmonization. The chills and fever treated by Shanzhuyu Rou (the flesh of Corni Fructus) are caused by internal injury of the Jueyin meridian, such as extreme Liver deficiency leading to alternating cold and heat, and sweating with a sensation of collapse; therefore, it is appropriate to use Shanzhuyu for tonification and astringency. Although the chills and fever in these two conditions appear similar, their etiologies are worlds apart. Clinicians must examine carefully and must not prescribe erroneously.

Chaihu is not an herb for inducing sweating, but in large doses, it can cause sweating. In Xiao Chaihu Tang (Minor Bupleurum Decoction), the dose of Chaihu is up to eight liang. Calculated according to modern weights and divided by three (since ancient prescriptions were decocted once and taken in three servings), one prescription yields approximately eight qian. The reason for using such a large amount of Chaihu in Xiao Chaihu Tang is to borrow the power of Chaihu to lift and raise the Shaoyang pathogens so they may emerge through the diaphragm upwards. However, using large doses risks causing peripheral sweating, which would dilute the upward-lifting force. Therefore, the instruction in Xiao Chaihu Tang to strain the decoction and re-boil it serves to reduce its sweating-inducing potency.

One might doubt: if Xiao Chaihu Tang is not a sweating agent, why does Article 149 of *Shanghan Lun* (Treatise on Cold Pathogenic Diseases) state that after taking Chaihu Tang, the patient sweats and recovers? One should understand that the context of this article specifically addresses cases where Xiao Chaihu Tang is administered following an erroneous purgative treatment. Xiao Chaihu Tang is a harmonizing formula, not a sweating formula. However, after erroneous purgation, external pathogens gathered in the hypochondrium may scatter into the Hand-Shaoyang Sanjiao (Triple Burner). Since Shaoyang is a pathway for circulation, the Hand and Foot Shaoyang meridians are interconnected. At this point, administering Xiao Chaihu Tang for harmonization allows the pathogens scattered in the Sanjiao to exit via the exterior channels of the Hand-Shaoyang meridian through sweat. The pathogens remaining in the hypochondrium, seeking resonance with those in the Sanjiao, also take the path of the Hand-Shaoyang meridian to resolve via sweat. Hence, the term "que" (yet/instead) is added before "fever and sweating," indicating that recovery is achieved through sweating not by forcing sweat, but as a result of resolution. Nevertheless, resolution via sweating from the Foot-Shaoyang meridian is not the standard route. After taking Xiao Chaihu Tang, the pathogens in the hypochondrium desire to rise and emerge through the diaphragm, but due to Qi deficiency caused by purgation, they cannot pass easily. The pathogens scattered in the Hand-Shaoyang meridian attract each other, opening a collateral pathway when accumulation reaches its peak. At this moment, there is a tendency for Righteous Qi to be unable to overcome Pathogenic Qi. Thus, there is first a sensation of intense internal heat followed by trembling, showing a strong struggle between Righteous and Pathogenic Qi, before fever and sweating occur to resolve the condition. This is known as "shivering before sweating." Observing that patients who took Chaihu Tang after purgation found it difficult to sweat confirms that resolution via sweating from the Foot-Shaoyang meridian is indeed not the primary route. Therefore, in my clinical practice, when using Xiao Chaihu Tang for robust individuals, I often remove Renshen (Ginseng Radix et Rhizoma); however, for patients who have undergone erroneous purgation, if I use Xiao Chaihu Tang, I must include Renshen to assist the body's strength to overcome the pathogen.

When using Chaihu to treat external pathogens of the Shaoyang meridian, it is not necessary to observe alternating chills and fever. If one knows the patient suffers purely from external contraction and exhibits nausea with a desire to vomit, this indicates the disease is in the Shaoyang stage, seeking to ascend through the pivot mechanism of Shaoyang to emerge through the diaphragm. Treating with Xiao Chaihu Tang can yield immediate results; this follows the principle of treating upward-moving pathogenic mechanisms by dispersing them. In other cases, patients may not show alternating chills and fever nor dislike vomiting, but instead frequently spit out sticky saliva. This can also be diagnosed as a Shaoyang disease, treated with Xiao Chaihu Tang. This is because the pathway of Shaoyang relates to Taiyin Damp-Earth; the fatty membrane surrounding the Spleen is close to the visceral fat (ban you), which is also fatty tissue, implying an affinity of like substances. This represents Shaoyang attempting to transmit to Taiyin. The Damp-Earth Qi of Taiyin, refined by the Fire of Shaoyang, condenses into sticky saliva that is frequently spat out. Administering Xiao Chaihu Tang can block the path into Taiyin, allowing resolution via the Shaoyang meridian. Furthermore, Chaihu is the principal herb for malaria. Some overly cautious practitioners suggest substituting Qinghao (Artemisiae Annuae Herba) if the patient has Yin deficiency with dry-heat. They fail to realize that malaria pathogens lodge in the fatty tissues beneath the hypochondrium, the major hub of the Foot-Shaoyang meridian. Chaihu can enter this area and lift the malaria pathogens to emerge through the diaphragm, whereas Qinghao lacks this lifting power. For patients with Yin deficiency or Heat entering the Blood level, one may appropriately add herbs that nourish Yin and cool Blood; for those with Dry-Heat or Excess Heat in the Qi level, one may add herbs that moisten dryness and clear Fire. Thus, in my treatment of malaria, I have cured cases by heavily using Dihuang (Rehmanniae Radix, raw or prepared), Shigao (Gypsum Fibrosum), and Zhimu (Anemarrhenae Rhizoma); for Qi deficiency, I have used heavy doses of Renshen (Ginseng Radix et Rhizoma) [text missing, likely Dangshen or Xiyangshen]; yet in all formulas, Chaihu was indispensable.

[Attached Case]: A man over forty years old suffered from swelling and pain in the hypochondrium, with no bowel movement for seven or eight days. The physician prescribed Dachengqi Tang (Major Order the Qi Decoction). The bowels did not open, and the hypochondriac pain worsened. His pulse was wiry and forceful, indicating excessive Liver Qi and Gallbladder Fire. I prescribed Jinling Xiegan Tang (Goldbell Liver-Draining Decoction) formulated by myself, adding Chaihu and Longdancao (Gentianae Radix), four qian each. Shortly after ingestion, the bowels moved, and the hypochondriac pain ceased instantly. Examining this case, the statement in *Shennong Bencao Jing* that "Chaihu treats dietary accumulation in the intestines and stomach, pushing out the old and promoting the new" is indeed not empty words. Moreover, it not only promotes bowel movements; medical texts also frequently use it to promote urination. My trials have proven quite effective. Generally, the downward flow of urine must pass through the Hand-Shaoyang Sanjiao. The Qi transformation of the Sanjiao must ascend before it can descend. Chaihu not only lifts the Foot-Shaoyang but also assists in lifting the Hand-Shaoyang.