于桂枝汤方内，加附子一枚，余根据桂枝汤法。
【集解】
柯琴曰：是方以附子加入桂枝汤中，大补表阳也。表阳密，则漏汗自止，恶风自罢矣
。汗止津回，则小便自利，四肢自柔矣。汗漏不止与大汗出同，而从化变病则异。服
桂枝麻黄汤，大汗出后，而大烦渴，是阳陷于里，急当救阴，故用白虎加人参汤。服
桂枝麻黄汤发汗，遂漏不止，而不烦渴，是亡阳于外，急当救阳，故用桂枝加附子汤
。要之，发汗之剂，用桂枝不当，则阳陷于里者多，用麻黄不当，则阳亡于外者多。
因桂枝汤有芍药而无麻黄，故虽汗大出而元府尚能自闭，多不致亡阳于外耳。
服桂枝汤，大汗出后，大烦渴不解，脉洪大者，白虎加人参汤主之。
【注】
大烦渴，阳明证也。洪大，阳明脉也。中风之邪，服桂枝汤，大汗出后不解，大烦渴
脉洪大者，是邪已入阳明，津液为大汗所伤，胃中干燥故也。宜与白虎加人参汤，清
热生津，而烦渴自除矣。
【集注】
张璐曰：白虎汤，实解内蒸之热，非治外轻之热也。昔人以石膏辛凉，能解利阳明风
热，若不佐以麻、葛之品，何以走外？此说似是而实非。盖阳明在经之邪，纵使有大
热而不烦渴，自有葛根汤、桂枝加葛根汤等治法，并无借于石膏。
在桂枝汤的方剂中，加入附子一枚，其余部分均依照桂枝汤的煎服方法。
【集解】
柯琴说：此方将附子加入桂枝汤中，旨在大力温补表阳（体表的阳气）。表阳固密，则漏汗自然停止，恶风症状自然消除。汗止津液恢复，则小便自然通利，四肢自然柔和。汗漏不止与大汗出虽然表现相似，但病机转化后的病变却不同。服用桂枝汤或麻黄汤后，若大汗出后出现大烦渴，这是阳气内陷于里，急需救阴，所以使用白虎加人参汤。服用桂枝汤或麻黄汤发汗后，导致汗漏不止，且不出现烦渴，这是阳气亡失于外，急需救阳，所以使用桂枝加附子汤。总之，发汗的药剂，如果使用桂枝不当，则容易导致阳气内陷；如果使用麻黄不当，则容易导致阳气亡失于外。因为桂枝汤中有芍药而没有麻黄，所以即使汗出很多，毛孔（元府）尚能自行闭合，大多不会导致阳气亡失于外。服用桂枝汤后，大汗出，随后出现大烦渴且不解，脉象洪大的，以白虎加人参汤为主治方。
【注】
大烦渴，属于阳明证（阳明经的病证）。洪大脉，属于阳明脉。中风之邪，服用桂枝汤后，大汗出而病不解，出现大烦渴、脉洪大，这是邪气已传入阳明，津液被大汗所伤，胃中干燥所致。适宜给予白虎加人参汤，以清热生津，则烦渴自然消除。
【集注】
张璐说：白虎汤，实际上是解除内部蒸腾的热邪，并非治疗体表轻微的热邪。过去有人以为石膏性味辛凉，能解除阳明风热，如果不配合麻黄、葛根这类药物，怎么能透达体表？这种说法看似有理实则错误。盖阳明在经之邪，即使有大热但不烦渴，自有葛根汤、桂枝加葛根汤等治疗方法，并不需要借助石膏。
Within the formula of Guizhi Tang (Cinnamon Twig Decoction), add one Fuzi (Aconiti Lateralis Radix Praeparata). The remainder follows the preparation and administration method of Guizhi Tang.
[Collected Explanations]
Ke Qin stated: This formula adds Fuzi to Guizhi Tang, aiming to strongly tonify the Exterior Yang (Yang qi at the body surface). When the Exterior Yang is secure, spontaneous leakage of sweat will stop naturally, and aversion to wind will cease. Once sweating stops and fluids return, urination will become normal naturally, and the limbs will become supple naturally. Although continuous leakage of sweat and profuse sweating are similar in presentation, the pathological changes that follow differ. After taking Guizhi Tang or Mahuang Tang (Ephedra Decoction), if profuse sweating is followed by severe restlessness and thirst, this indicates Yang sinking into the interior, requiring urgent preservation of Yin; thus, Baihu Jia Renshen Tang (White Tiger Plus Ginseng Decoction) is used. If taking Guizhi Tang or Mahuang Tang for sweating leads to continuous leakage without restlessness or thirst, this indicates Yang loss on the exterior, requiring urgent rescue of Yang; thus, Guizhi Jia Fuzi Tang (Cinnamon Twig Plus Aconite Decoction) is used. In summary, with diaphoretic agents, improper use of Guizhi often leads to Yang sinking into the interior, while improper use of Mahuang often leads to Yang loss on the exterior. Because Guizhi Tang contains Shaoyao (Paeoniae Radix Alba) but lacks Mahuang, even with heavy sweating, the pores (Yuanfu) can still close themselves, so it rarely results in Yang loss on the exterior. After taking Guizhi Tang, if profuse sweating occurs followed by unrelieved severe restlessness and thirst, and the pulse is flooding and large, Baihu Jia Renshen Tang should be administered as the primary treatment.
[Annotation]
Severe restlessness and thirst constitute a Yangming syndrome (disease pattern of the Yangming channel). A flooding and large pulse is characteristic of Yangming. For pathogenic wind-strike, after taking Guizhi Tang, if profuse sweating occurs and the condition does not resolve, presenting with severe restlessness, thirst, and a flooding-large pulse, this indicates the pathogen has entered Yangming. Body fluids have been damaged by profuse sweating, causing dryness in the Stomach. It is appropriate to administer Baihu Jia Renshen Tang to clear heat and generate fluids, thereby eliminating restlessness and thirst.
[Collected Notes]
Zhang Lu stated: Baihu Tang (White Tiger Decoction) actually resolves internal steaming heat, rather than treating mild exterior heat. Some previously believed that Shigao (Gypsum Fibrosum), being acrid and cool, could resolve Yangming wind-heat; however, without assisting herbs like Mahuang or Gegen (Puerariae Lobatae Radix), how could it reach the exterior? This argument seems plausible but is fundamentally incorrect. Regarding pathogens in the Yangming channel, even if there is significant heat without restlessness and thirst, there are existing treatments such as Gegen Tang (Kudzu Root Decoction) or Guizhi Jia Gegen Tang (Cinnamon Twig Plus Kudzu Root Decoction); reliance on Shigao is unnecessary.