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Taiyang (Sun Yang) governs the exterior, therefore prescriptions for it primarily focus on releasing the exterior. However, within this release of the exterior, there is also concurrent treatment of the interior, resulting in a variety of different formulas. Mahuang Tang (Ephedra Decoction) descends rebellious Qi while releasing the exterior; Guizhi Tang (Cinnamon Twig Decoction) nourishes Yin while releasing the exterior; Gegen Tang (Kudzu Root Decoction) generates fluids while releasing the exterior; Da Qinglong Tang (Major Blue Green Dragon Decoction), Ma Xing Gan Shi Tang (Ephedra, Apricot Kernel, Licorice, and Gypsum Decoction), and Ma Lian Qiao Chi Dou Tang (Ephedra, Forsythia, and Adzuki Bean Decoction) clear fire while releasing the exterior; Xiao Qinglong Tang (Minor Blue Green Dragon Decoction) and Wuling San (Five-Ling Powder) promote diuresis while releasing the exterior. There are degrees of lightness and heaviness in clearing fire, and depths in promoting diuresis. As for Baihu Tang (White Tiger Decoction) clearing fire and Shizao Tang (Ten Jujube Decoction) promoting diuresis, these are treatments for conditions after the exterior has been resolved. The formulas such as Xuanxiong Tang (Chest-Draining Decoction), Xiexin Tang (Heart-Draining Decoction), Didang Tang (Visit the Palace Decoction), Tiaoweichengqi Tang (Regulate the Stomach and Purge Accumulation Decoction), Sini Tang (Reverse Cold Decoction), and Zhenwu Tang (True Warrior Decoction) are methods to rescue deviation according to symptoms. Generally speaking, diseases of the Taiyang exterior do not depart from the modifications of Guizhi Tang and Mahuang Tang, because the Heart is the interior of Taiyang. Now, I will discuss these formulas in detail to highlight Zhang Zhongjing’s therapeutic methods, allowing future generations to use them boldly. Thus, sayings such as "Mahuang Tang treats Shanghan (Cold Damage) but not Fengzhong (Wind Strike), and Guizhi Tang treats Fengzhong but not Shanghan" can be somewhat silenced.

Guizhi Tang:
Guizhi (Cinnamon Twig), Shaoyao (Peony Root), Gancao (Licorice Root), Shengjiang (Fresh Ginger), Dazao (Jujube Fruit)
This is the leader among Zhang Zhongjing’s group of formulas. It is the general formula for nourishing Yin and harmonizing Yang, harmonizing Ying (Nutritive) and Wei (Defensive), releasing the muscle layer, and inducing sweating. For any patient with headache, fever, aversion to wind or cold, with a floating and weak pulse, and spontaneous sweating, regardless of which meridian is involved, and whether it is Fengzhong, Shanghan, or miscellaneous diseases, this formula should be used to induce sweating. If improper sweating or purging was performed and the exterior condition remains unresolved, this formula should still be used to release the muscle layer. Regarding symptoms such as headache, fever, aversion to cold, aversion to wind, nasal congestion with roaring, and dry vomiting, if even one symptom is present, it is sufficient; they need not all be present. The primary indicators are a weak pulse and spontaneous sweating. Guizhi is red in color, enters the Heart, warms the meridians, and can support Yang to scatter cold. Its sweet taste benefits Qi and generates Blood; its pungent taste disperses external pathogens. Internally, it assists the Sovereign (Heart), stimulates Heart fluids to become sweat. Therefore, in formulas like Mahuang, Gegen, and Qinglong that induce sweating to ward off cold, Guizhi is always used. However, Guizhi Tang must not contain Mahuang, and Mahuang Tang cannot lack Guizhi. This formula consists mainly of pungent and sweet dispersing agents. Only Shaoyao is slightly bitter and slightly cold, capable of benefiting Yin and astringing Blood, and internally harmonizing Ying Qi. Ancestors stated that those without sweating cannot use Guizhi Tang because Shaoyao can stop sweating. The function of Shaoyao is originally to stop irritability; when irritability stops, sweating also stops. Therefore, cases of reversed irritability, increased irritability, palpitations with irritability, all rely on it. If the dosage of Shaoyao is doubled, it becomes a Jianzhong (Establish the Middle) type formula, not a formula for re-inducing sweating. In this formula, Guizhi induces sweating, while Shaoyao stops sweating. The pungency of Shengjiang assists Guizhi in releasing the muscle layer; the sweetness of Dazao assists Shaoyao in harmonizing the interior. Guizhi and Shaoyao complement each other; Shengjiang and Dazao are in harmony. Yin and Yang, interior and exterior, proceed together without contradiction; this is achieving harmony through the mutual assistance of rigid and soft properties. Gancao is sweet and neutral, possessing the power to secure the interior and repel the exterior. It is used to harmonize Qi and Blood, which is essentially harmonizing the interior and exterior, and also to harmonize the various herbs. The essence lies particularly in drinking hot thin porridge to assist the medicinal power. When grain Qi is充盈 (full) inside, external pathogens cannot enter again. Drinking hot porridge after taking the medicine ensures residual pathogens do not remain. This is another subtle use of compound formulas. Thus, using it to induce sweating will not lead to loss of Yang; using it to stop sweating will not leave behind trouble. Nowadays, whenever people encounter fever, regardless of deficiency or excess, they avoid grain foods. Those who publish Guizhi Tang formulas delete this method of drinking porridge. How could they understand Zhang Zhongjing’s core principles? One must know that this formula specifically treats exterior deficiency. It can only release the muscle layer and induce sweating from the Ying level; it cannot open the pores to expel pathogens from the Wei level. Therefore, if there is no sweating, it is a Mahuang Tang syndrome; if the pulse is floating and tight, it is a Mahuang Tang pulse, and Guizhi Tang should not be used. However, at the onset with no sweating, Mahuang Tang should be used to induce sweating. If irritability recurs after sweating, even if the pulse is floating and rapid, Mahuang Tang should not be given again; instead, Guizhi Tang should be used. If the disease does not resolve after sweating, or if the pulse remains floating after purging, with Qi rushing upward, or if diarrhea stops but body pain persists, this formula should be used to release the exterior. At this time, although the exterior is not resolved, the cou li (pores/skin texture) have loosened, and the pathogen is no longer in the skin and hair but in the muscles. Therefore, although the pulse and symptoms may resemble Mahuang Tang, the treatment belongs to Guizhi Tang. Unskilled physicians wrongly claim that Guizhi Tang exclusively treats Fengzhong, binding the eyes and ears of later generations. Moreover, the "Fengzhong" they describe does not match this formula, so they discard it. I often use this decoction to treat spontaneous sweating, night sweating, deficiency malaria, and deficiency dysentery, curing them readily. From this, I know that Zhang Zhongjing’s formulas can treat hundreds of diseases. Can this be compared to later generations’ categorization of syndromes that leaves practitioners with nowhere to start?

Mahuang Tang:
Mahuang (Ephedra Herb), Guizhi (Cinnamon Twig), Xingren (Apricot Kernel), Gancao (Licorice Root)
It treats Wind-Cold in the exterior, causing headache and stiff neck, fever and body pain, lower back pain, severe bone joint pain, aversion to wind and cold, absence of sweating, chest fullness with wheezing, with a floating-tight or floating-rapid pulse. This is a potent formula for opening the exterior, driving out pathogens, and inducing sweating. Ancient doctors used the principle of image-based medication. Mahuang is hollow inside and straight outside, resembling hair follicles and bone joints, thus it can remove Wind-Cold from the joints and expel it through the pores. It is a herb for the Wei level to disperse Wind-Cold. Guizhi branches crisscross, resembling meridians and collaterals; it enters the Heart to transform fluids, unblocks meridians to induce sweating, and is a herb for the Ying level to resolve Wind-Cold. Xingren is a fruit of the Heart; its warmth assists the Heart in scattering cold, and its bitterness clears the Lung and directs Qi downward. It is a herb for the Upper Jiao to drive out pathogens and calm wheezing. Gancao is sweet and neutral, repelling Wind-Cold externally and harmonizing Qi and Blood internally. It is a herb for the Central Jiao to secure the interior and repel the exterior. This decoction, upon entering the stomach, circulates Qi through the xuanfu (pores), and transmits essence to the skin and hair. When hair and vessels combine their essence, profuse sweating occurs. Pathogens in the exterior are completely eliminated without leaving residue. Pain stops, wheezing calms, and chills and fever resolve instantly. There is no need to drink porridge to borrow grain Qi for sweating. It does not use Shengjiang and Dazao because Shengjiang’s nature spreads horizontally to release the muscle layer, hindering Mahuang’s ascending action; Dazao’s nature is sticky and obstructs the diaphragm, hindering Xingren’s rapid descent. This is to achieve rapid direct action; if slowed, it is not swift; if spread horizontally, it is not potent. If the pulse is floating-weak with spontaneous sweating, or if the chi (cun-guan-chi) pulse is faint and slow, this is indicated for Guizhi Tang, not suitable for this formula. This is a pure Yang formula, overly dispersing, like a general charging straight ahead. If applied correctly, victory is achieved in one battle; if incorrect, failure brings disaster. Therefore, when using it to release the exterior, it can be used once but not repeatedly. If the disease does not resolve after sweating, it should be replaced by Guizhi Tang. If sweating is incomplete and pathogens linger between skin, hair, bones, and muscles, there are the ingenious uses of Mahui Banxia Tang (Half-Ephedra Half-Cinnamon Twig Decoction) and Guizhi Er Mahuang Yi Tang (Two-Parts Cinnamon Twig One-Part Ephedra Decoction). If Yang is excessive internally with no sweating, there are formulas like Mahuang Xingren Shigao Lianqiao Chidou Tang. These are all Zhang Zhongjing’s core methods. I treat cold-wind asthma and bi-syndrome caused by the combination of Wind, Cold, and Dampness with this formula, and it is often effective. It is not limited to Shanghan alone. Note: Regarding Mahuang and Guizhi formulas treating Shanghan and Fengzhong, practitioners hesitate to use them when appropriate, while commentators wrongly claim they are appropriate when they are not. For example, the statement "Taiyang nosebleed syndrome should use Guizhi Tang" implies that sweating or purging is required at that juncture. The phrase "Mahuang zhu zhi" (Mahuang Tang governs it) implies inducing sweating or purging. These two phrases are added at the end as a reverse order technique. Zhang Zhongjing explains the rationale in detail during syndrome differentiation but does not mention the formula yet. Guizhi promotes blood circulation. Zhang Zhongjing uses Guizhi to induce sweating, not to stop nosebleeds. It is used before bleeding occurs, not after. Moreover, those who lose blood cannot sweat; this logic is clear. Mahuang is an ascending herb. Since it is said that nosebleed leads to resolution, and spontaneous nosebleed leads to healing, reusing an ascending drug would inevitably cause continuous bleeding. Furthermore, those with chronic nosebleeds cannot undergo sweating therapy; this prohibition is very clear. Similarly, the phrase "Xiao Qinglong zhu zhi" implies after taking the medicine. Would one use a drying-hot formula when cold has gone and resolution is desired, thereby destroying fluids and causing unquenchable thirst? And what medicine is referred to by "after taking medicine"? Observe that Zhang Zhongjing explicitly criticizes inappropriate medications, such as "After taking Xiexin Tang, purged with another medicine, diarrhea did not stop," or "Knowing the doctor purged with another medicine, this was not the correct treatment." Unskilled doctors do not understand reverse order techniques and are obsessed with the terms Wind and Cold, claiming that even with severe heat, since the pathogen is in the meridian, using Mahuang for nosebleed is merely dispersing meridian pathogens. Ask yourself: Is the pathogen Cold or Heat? If Cold, blood coagulates and does not flow, how can there be nosebleed? If Heat, one should clear and descend urgently, how dare one ascend and disperse? Also, it is said that if bleeding is scanty, medication is necessary. If it flows continuously, what method is used to manage it afterwards? This error harms the common people the most. I hereby expose and clarify it.

Gegen Tang:
Gegen (Kudzu Root), Mahuang (Ephedra Herb), Guizhi (Cinnamon Twig), Baishao (White Peony Root), Gancao (Licorice Root), Jiang (Ginger), Zao (Jujube)
It treats stiffness and pain in the head and neck, stiffness in the back, pulling sensations, floating pulse, absence of sweating, and aversion to cold. It also treats self-directed diarrhea due to Wind-Cold in the exterior. This is a mild formula for opening the exterior and driving out pathogens. The symptoms include no body pain, no lower back pain, no joint pain, indicating the bones are not affected by Cold. Head and neck stiffness extending to the back with pulling discomfort indicates tendons injured by Wind. No wheezing, no irritability, no dry vomiting indicates no internal syndrome. Absence of sweating and aversion to wind indicates the disease is solely in the exterior. If exterior disease is accompanied by diarrhea, it is Exterior Excess and Interior Deficiency. It is milder than Mahuang Tang and Qinglong Tang formulas. However, the neck-back stiffness is more severe than simple neck stiffness. Absence of sweating still constitutes Exterior Excess. The pulse is floating but not tight or rapid, indicating invasion by the moving Yang-Wind. Therefore, Guizhi Tang is the base, with added Mahuang and Gegen to attack the Exterior Excess. Gegen is sweet and cool in nature. It raises Yin Qi and generates fluids, nourishes tendons and meridians, and relieves pulling. Thus, it serves as the Sovereign herb. Mahuang and Shengjiang open the closure of xuanfu and cou li, dispel Wind, and induce sweating, serving as Minister herbs. Since both Cold and Heat are mild, small amounts of Guizhi and Shaoyao are added, along with Gancao and Dazao, to harmonize the interior. This formula balances the weight between Mahuang and Guizhi formulas, serving as a formula to harmonize the exterior and interior. Thus, when used for Exterior Excess, external pathogens resolve naturally. There is no need to treat Interior Deficiency directly, and diarrhea heals itself. This differs from Da Qinglong Tang, which treats simultaneous Exterior and Interior Excess. One must know that Gegen has a light and clear nature but a heavy substance. Lightness can remove excess; heaviness can calm agitation; density can secure the interior. It possesses three virtues in one herb. However, it is only suitable for Exterior Excess and Interior Deficiency. It is not suitable for Stomach Excess. Therefore, Zhang Zhongjing does not use Gegen in the Yangming Meridian chapter. Li Dongyuan categorized herbs by meridian, placing Gegen in Yangming rather than Taiyang. Yi Lao said, "Do not take if it has not entered Yangming." Both fail to understand this meaning. Yu Jia Yan claimed "Zhang Zhongjing does not use it in Yangming to prevent fluid loss," which contradicts the Ben Cao (Materia Medica) saying it generates fluids. He also claimed it "opens the muscle layer," contradicting Zhang Zhongjing’s addition of Gegen to Guizhi Tang for sweating and aversion to wind. Essentially, both Guizhi and Gegen are formulas that release the muscle layer and harmonize the interior. Therefore, they can be used whether there is sweating or not, and whether there is diarrhea or not. This differs from Mahuang, which specializes in treating the exterior. Both Mahuang and Gegen have foam when boiled; foam represents turbid Qi. Therefore, Zhang Zhongjing boils them first to remove the foam before adding other herbs. This takes advantage of their clear and ascending nature to open the cou li. The reason for drinking thin porridge with Guizhi Tang is that without Mahuang’s opening power, there is Shaoyao’s astringent power. Fearing pathogens may not be fully expelled, grain Qi is borrowed to drive them out. This is where sweat is born from grain.

Da Qinglong Tang:
Mahuang (Ephedra Herb), Guizhi (Cinnamon Twig), Shigao (Gypsum Fibrosum), Xingren (Apricot Kernel), Gancao (Licorice Root), Jiang (Ginger), Zao (Jujube)
Taiyang Fengzhong, with a floating-tight pulse, headache, fever, aversion to cold, body pain, absence of sweating, and irritability. This is a severe form of the Mahuang Tang syndrome, hence modified to treat it. All symptoms are those of Mahuang Tang, distinguished by wheezing versus irritability. Wheezing is caused by Cold stagnating Qi, preventing free ascent and descent, so a larger amount of bitter Xingren is used to direct Qi downward. Irritability is caused by Heat damaging Qi and lacking fluids to produce sweat, so specific addition of sweet Shigao is used to generate fluids. However, Shigao is heavy and extremely cold. Fearing that internal heat is suddenly cleared while exterior Cold remains unresolved, leading to Cold in the Middle with accompanying heat-induced diarrhea (inviting the thief to break into the house), one must double the dose of Mahuang to release the exterior, double Gancao to harmonize the Middle, and use Jiang and Zao to regulate Ying and Wei. A single sweat resolves both interior and exterior, eliminating both Wind and Heat. This demonstrates Da Qinglong Tang’s power to clear the interior and repel the exterior, supplementing the deficiencies of Mahuang and Guizhi formulas. The name Qinglong (Blue Green Dragon) refers to inducing sweating. The distinction between Large and Small Qinglong lies in the amount of Mahuang, not Shigao, as seen in Xiao Qinglong Tang which does not use Shigao. Shigao cannot驱散 (dispel) Wind-Cold in the exterior; it only clears blazing heat in the Middle Jiao, as seen in the frequent use of Baihu Tang. People today do not know that Shigao is for irritability, mistakenly thinking it is for inducing sweating. The "Light can remove Excess" category in the Ten Formulas—how can a substance of extreme hardness and weight induce sweating? The error of excessive sweating leading to loss of Yang lies with Mahuang. Shaoyin (Lesser Yin) also presents with fever, aversion to cold, and irritability, similar to Da Qinglong Tang, but differs in that the pulse is not floating and the head does not hurt. If the pulse is floating-weak with spontaneous sweating, it is a Guizhi syndrome. Using Shigao recklessly in these cases prevents Stomach Qi from reaching the limbs, causing cold hands and feet. Using Mahuang recklessly prevents Wei Yang from circulating the body, causing muscle twitching. These are deeply cautioned against by Zhang Zhongjing. One must know that if Shaoyin presents with Yang symptoms and Mahuang is used, it must be secured with Fuzi (Aconite Root). Taiyang and Shaoyin occupy different positions and follow different paths of Yin and Yang, so Cold and Warmth therapies differ. The irritability in Guizhi syndrome stems from Wood hyperactivity, treated with slightly bitter and slightly cold agents to regulate ascent and descent. The restlessness accompanying irritability in Da Qinglong Tang stems from Wind agitation, treated with extremely Yin and heavy substances to suppress it. Presence or absence of sweating, deficiency or excess, determine the severity. One must carefully examine what is contraindicated to ensure correct usage.
Note: Xu Shuwei said, "Guizhi treats Fengzhong, Mahuang treats Shanghan, Da Qinglong treats Fengzhong presenting with Han pulse, and Shanghan presenting with Feng pulse. The three stand like a tripod." This is the origin of Fang’s Three Major Principles. Consequently, the syndrome and treatment of Da Qinglong Tang became unclear in the world. One does not realize that Zhang Zhongjing’s treatment of the exterior relies only on Mahuang and Guizhi methods. Mahuang treats Exterior Excess; Guizhi treats Exterior Deficiency. Formula application is divided by Excess and Deficiency, not by Wind and Cold. Both Wind and Cold syndromes have Excess and Deficiency, depth and shallowness, and involve Ying and Wei. The major principle divides depth and shallowness by Excess and Deficiency, not by Ying and Wei of Wind and Cold. Sweating indicates Exterior Deficiency; Guizhi Tang is established to treat Wind-Cold with sweating. Modifications include adding/removing Guizhi, adding/removing Shaoyao, and adding Fuzi, Renshen, Houpo, Xingren, Fuling, Baizhu, Dahuang, Longgu, Muli, etc. These are all variations of Guizhi Tang. Because Interior Deficiency and Excess vary in depth within Exterior Deficiency, modification methods vary greatly. Absence of sweating indicates Exterior Excess; Mahuang Tang is established to treat Wind-Cold without sweating. However, Exterior Excess may also involve夹杂 (mixing) Cold/Summerheat, Internal Cold/Internal Heat. Thus, based on Mahuang, modifications include Gegen Tang, Large/Small Qinglong Tang, Mahuang Fuxi Xixin Gancao Tang, Mahuang Xingren Gancao Shigao Tang, Ma Lian Qiao Chi Dou Tang, etc. These are all variations of Mahuang Tang. Because Exterior Excess varies in Internal/External Cold/Heat depth. Gegen Tang adds Shaoyao and Gegen due to insufficient muscle fluids; Da Qinglong Tang adds Shigao due to internal heat and irritability; Xiao Qinglong Tang adds Banxia, Xixin, Ganjiang due to dry retching and coughing; Mahuang Fuxi Xixin Gancao Tang adds Fuzi due to deep pulse; Lianqiao Chidou Zibi is added for damp-heat jaundice. All these formulas are based on Exterior Excess and modified from Mahuang Tang. Why single out Da Qinglong Tang as standing apart? Why only know of Wind-Cold and not Wind-Heat? Why only know of Fengzhong with Han pulse and Shanghan with Feng pulse, and not know that Xiao Qinglong Tang treats Wind-Cold, Da Qinglong Tang treats Wind-Heat, Ma Xing Gan Shi Tang treats Warm-Thermal, and Ma Qiao Dou Tang treats Damp-Heat, showing further distinctions within Exterior Excess? Moreover, ancestors who rigidly divided Wind and Cold were constrained by pulse diagnosis. They did not know Zhang Zhongjing’s pulse discussion is flexible. For example, in the Da Qinglong Tang clause, there is Fengzhong with floating-tight pulse and Shanghan with floating-slow pulse. This is intertextual implication. It means Fengzhong usually has a slow pulse, but can have a floating-tight one; Shanghan usually has a tight pulse, but can have a floating-slow one. Fengzhong and Shanghan have varying depths, differing by individual strength, geographical altitude, and seasonal harmony. Since syndromes cannot be rigidly defined, pulses cannot be dogmatically held. For instance, Yangming Fengzhong can have a floating-tight pulse, and Taiyin Shanghan can have a floating-slow pulse. One cannot say tight pulse must be Shanghan and slow pulse must be Fengzhong. According to Nei Jing, a slippery pulse indicates Wind, so Wind pulse has no fixed image. A full and tight pulse indicates distension, so tight pulse is not exclusive to Shanghan. A slow and slippery pulse indicates internal heat, so slow pulse does not exclusively refer to Fengzhong. Furthermore, Yangming Fengzhong can have a floating-tight pulse or a string-like, floating, large pulse. Insisting on dividing Wind and Cold by Taiyang’s slow-pulse-with-sweating and tight-pulse-without-sweating splits Ying and Wei arbitrarily. Other meridians also have Fengzhong, why are they not mentioned? One must know that a tight pulse is definitely forceful, and a floating-slow pulse is not necessarily floating-weak; it corresponds to the Nei Jing’s slow-and-slippery pulse for internal heat. Zhang Zhongjing diagnoses based on pulse and syndrome, focusing only on Excess and Deficiency. Therefore, regardless of whether the pulse is slow or tight in Fengzhong or Shanghan, forceful under the fingers indicates Excess; weak and powerless indicates Deficiency. No sweating with irritability indicates Excess; profuse sweating with irritability indicates Deficiency. Irritability in Taiyang indicates Excess; irritability in Shaoyin indicates Deficiency. Excess can take Da Qinglong Tang; Deficiency cannot. This is easy to understand. Those who are irritable but not restless with a floating pulse will likely sweat and resolve spontaneously. Those who are irritable and restless with a floating-tight pulse will likely have no sweating and not resolve. Da Qinglong Tang is designed for Wind-Cold in the exterior combined with internal heat. It is not designed for exterior-only conditions. Therefore, it can be used for Fengzhong without sweating and irritability, and for Shanghan without sweating and irritability. Wind and Cold are fundamentally one Qi, so the decoctions can be interchangeable. The text mentions Fengzhong and Shanghan interchangeably, such as in Da Qinglong Tang; and jointly, such as in Xiao Chaihu Tang. Zhang Zhongjing simply differentiates pulse and syndrome to apply treatment. Did he ever rigidly distinguish the names Fengzhong and Shanghan? If Mahuang Tang treats Cold and Guizhi Tang treats Wind, why not use Guizhi Mahuang Banxia Tang for Fengzhong with Cold signs and Shanghan with Wind signs, but instead use Da Qinglong Tang as the main treatment? Furthermore, if there is a theory that Fengzhong involves aversion to wind but not cold, and Shanghan involves aversion to cold but not wind, why not assign Da Qinglong Tang’s aversion to cold to Shanghan, Mahuang syndrome’s aversion to wind to Fengzhong, and Guizhi syndrome’s aversion to wind and cold to Fengzhong with Cold/Shanghan with Wind? Fang Shi had a crude view of Wind-Cold proportions due to the Three Principles division. Yu Jia Yan created bizarre theories about dragon backs, bellies, and tails due to the name Da Qinglong Tang. He claimed the crisscrossing refers to the dragon’s flight position at Qimen and Da Qinglong. The more intricate the Dragon theory, the more obscured the Dragon method. This is called loving dragons but not knowing the true dragon. The key points of Da Qinglong Tang are "no sweating with irritability" and "no Shaoyin syndrome." Viewing them together, this formula is originally set for Taiyang irritability. Zhang Zhongjing fears people will misuse Qinglong; he not only prohibits it for those with weak pulses and sweating, but emphasizes especially Shaoyin. Shaoyin also presents with fever, aversion to cold, body pain, no sweating, and irritability. This is Extreme Yin resembling Yang, Extreme Cold manifesting as Heat transformation. Misuse will inevitably lead to reversal cold, limb cold, and muscle twitching. The crucial point lies here. One must ascertain it is not a Shaoyin syndrome, confirming it is undoubtedly Taiyang irritability. Taiyang irritability is Yang Excess, which cannot be resolved without Da Qinglong Tang.