（太阳入阳明去路）
阳盛之人表寒里热则用大青龙表寒解而里热盛于是有白虎清金之法肺金清而胃热消可无异日阳明之证矣至于汗后阳
虚之渴则于白虎而加人参凉金益气生津化水清涤烦渴之妙超人巧而绝天工制方立法神化难追然白虎汤证虽皆伤寒之条其
实来自中风者多如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其为风证甚明以中风多传阳明白虎汤证乃承
气证之初气也
伤寒脉滑而厥者里有热也白虎汤主之
四肢厥逆而脉见迟涩是为里寒厥而脉滑是里有热也盖燥热内郁侵夺阴位阴气浮散外居肢节故肢冷而脉滑白虎汤石膏
清金而退热知母润燥而泄火甘草粳米补中而化气生津而解渴也胃阳素盛之人阴虚火旺一被感伤经热内蒸津液消烁则成阳
明下证而胃火未盛肺津先伤是以一见渴证先以白虎凉金泄热滋水涤烦膈热整肃则不至入胃而致烦热亡阴之害矣白虎证即
将来之大承气证而里热未实从前之大青龙证而表寒已解者也表寒已解故不用麻黄里热未实故不用硝黄
石膏（一斤） 知母（六两） 甘草（二两） 粳米（六合）
上四味以水一升煮米熟汤成去滓温服一升日三服
伤寒脉浮滑此里有热表有寒也白虎汤主之
此申明上章未显之义脉滑者里有热也厥者表有寒也此不言厥者诊脉浮滑已知是表寒外束里热内郁不必问其肢节之厥
热矣若里热外发则脉变实缓不复浮滑也浮滑者阳气郁格之象也此之表寒乃阴气之外浮非寒邪之外淫不然表寒未解无用白
虎之理
（太阳病向阳明病转化的途径）
阳气旺盛的人，若感受表寒而体内有热，则使用大青龙汤。待表寒解除后，若里热依然炽盛，于是采用白虎汤清泻肺金的方法。肺金得以清肃，胃中的热邪随之消除，这样就不会发展成阳明病的证候了。至于发汗之后因阳气虚弱导致的口渴，则在白虎汤中加入人参，以凉润肺金、益气生津、化水行津，其清除烦渴的妙用超越人工巧思，堪称天工之作，方剂的制定与法度的确立神妙难测。然而，虽然白虎汤证都属于伤寒的条文范畴，但实际上多由中风病传变而来。例如服用桂枝汤后大汗出，出现严重烦躁且口渴不解，脉象洪大的情况，应用白虎加人参汤主治，这明显是风邪致病的表现。因为中风病多传入阳明经，白虎汤证实际上是承气汤证的初期阶段，即气分热盛的早期。
伤寒患者脉象滑利而四肢厥冷的，说明体内有热，应用白虎汤主治。
四肢厥冷逆乱且脉象见迟涩的，属于里寒厥；而脉象滑利的，则是里有热。这是因为燥热内郁，侵夺阴位，导致阴气浮散于外，居于肢节，所以出现肢体寒冷而脉象滑利。白虎汤中，石膏清泻肺金而退热，知母滋润燥热而泄火，甘草和粳米补益中气而化生精气，生津液而解口渴。对于胃阳素来旺盛之人，若阴虚火旺，一旦受到外感损伤，经气之热内蒸，津液被消烁，就会形成阳明腑实下证。但在胃火尚未极度亢盛、肺津先已受伤的情况下，一见口渴症状，就先以白虎汤凉润肺金、泄热滋水、清除膈间烦热。如此整肃热势，就不会使热邪入胃而导致烦热亡阴的危害了。白虎汤证即是将来可能发展为的大承气汤证，但此时里热尚未结实；也是从前的大青龙汤证，但表寒已经解除。因为表寒已解，所以不用麻黄；因为里热尚未结实，所以不用芒硝和大黄。
石膏（一斤） 知母（六两） 甘草（二两） 粳米（六合）
以上四味药，用水一斗，煮至米熟汤成，去渣，每次温服一升，每日三次。
伤寒患者脉象浮滑，这是里有热、表有寒的表现，应用白虎汤主治。
此处阐明上一章未显明的含义：脉滑代表里有热，四肢厥冷代表表有寒。这里没有提及四肢厥冷，是因为诊察到脉象浮滑，已知是表寒外束、里热内郁，不必询问其肢节是否有厥冷或发热。如果里热向外发散，脉象就会变为实缓，不再呈现浮滑之象。脉象浮滑，是阳气被郁遏格拒的现象。这里的“表寒”是指阴气之外浮，并非寒邪之外袭。否则，若表寒未解，就没有使用白虎汤的道理。
(Transition from Taiyang to Yangming)
In individuals with robust Yang, if exterior cold is contracted while interior heat exists, Da Qing Long Tang (Great Blue Dragon Decoction) is used. Once the exterior cold is resolved, if the interior heat remains excessive, Bai Hu Tang (White Tiger Decoction) is employed to clear Lung Metal (the organ system associated with metal in Five Phase theory). By clearing Lung Metal, stomach heat dissipates, preventing the progression to Yangming disease syndromes. Regarding thirst caused by Yang deficiency after sweating, Ren Shen (Ginseng Root) is added to Bai Hu Tang to cool Lung Metal, tonify Qi, generate fluids, and transform water. Its efficacy in clearing vexation and quenching thirst surpasses human ingenuity, resembling heavenly craftsmanship; the formulation and principles are divine and difficult to trace. However, although Bai Hu Tang syndromes appear under Shang Han (Cold Damage) chapters, they often originate from Zhong Feng (Wind Strike). For instance, after taking Gui Zhi Tang (Cinnamon Twig Decoction), profuse sweating occurs, followed by severe vexation and unrelenting thirst with a surging pulse; this is treated with Bai Hu Jia Ren Shen Tang (White Tiger Decoction plus Ginseng Root), clearly indicating a wind pathogen syndrome. Zhong Feng frequently transmits to Yangming; thus, the Bai Hu Tang syndrome represents the initial stage of Cheng Qi Tang (Order the Qi Decoction) syndrome, specifically the early phase of Qi-level heat.
In Shang Han, if the pulse is slippery and there is cold extremities (Jue), it indicates interior heat, treated with Bai Hu Tang.
Cold extremities with a slow and choppy pulse indicate interior cold Jue; however, a slippery pulse indicates interior heat. This is because dry-heat stagnates internally, invading Yin positions, causing Yin Qi to float outward to the limbs, resulting in cold extremities despite a slippery pulse. In Bai Hu Tang, Shi Gao (Gypsum Fibrosum) clears Lung Metal and reduces fever; Zhi Mu (Anemarrhenae Rhizoma) moistens dryness and drains fire; Gan Cao (Licorice Root) and Jing Mi (Oryza Sativa) tonify the Middle Jiao, transform Qi, generate fluids, and relieve thirst. In individuals with naturally strong Stomach Yang, if Yin deficiency leads to hyperactive fire, external contraction causes meridian heat to steam internally, consuming body fluids, which may lead to Yangming Fu-organ excess syndromes. However, before Stomach fire becomes extreme, Lung fluids are often injured first. Upon observing thirst, Bai Hu Tang is used initially to cool Lung Metal, drain heat, nourish water, and clear diaphragmatic heat. This rectifies the heat, preventing it from entering the Stomach and causing the harm of vexation, heat, and loss of Yin. The Bai Hu Tang syndrome is the precursor to the future Da Cheng Qi Tang (Great Order the Qi Decoction) syndrome, but interior heat is not yet solidified; it is also the state following the Da Qing Long Tang syndrome where exterior cold has been resolved. Since exterior cold is resolved, Ma Huang (Ephedrae Herba) is omitted; since interior heat is not yet solidified, Mang Xiao (Natrii Sulfas) and Da Huang (Rhei Radix et Rhizoma) are omitted.
Shi Gao (Gypsum Fibrosum) - 1 jin
Zhi Mu (Anemarrhenae Rhizoma) - 6 liang
Gan Cao (Licorice Root) - 2 liang
Jing Mi (Oryza Sativa) - 6 he
The above four ingredients are boiled in 10 sheng of water until the rice is cooked and the decoction is ready. Strain and take 1 sheng warm, three times daily.
In Shang Han, if the pulse is floating and slippery, it indicates interior heat and exterior cold, treated with Bai Hu Tang.
This clarifies the implicit meaning of the previous chapter: a slippery pulse indicates interior heat; cold extremities indicate exterior cold. Here, cold extremities are not mentioned because a floating and slippery pulse already indicates exterior cold binding and interior heat stagnating, making inquiry into limb temperature unnecessary. If interior heat were to erupt outward, the pulse would become full and slow, no longer floating and slippery. A floating and slippery pulse is a sign of Yang Qi being constrained and blocked. The "exterior cold" here refers to the outward floating of Yin Qi, not an invasion of external cold pathogens. Otherwise, if exterior cold were unresolved, there would be no rationale for using Bai Hu Tang.