(The substances with dense qi and flavor belong to the Yang within Yang. Their nature is warm and hot, inducing fever, and their taste is typically acrid and sweet.)

Guizhi (Cinnamon Twig): The qi is hot, the taste is sweet and acrid, with slight toxicity. It belongs to the Yang within Yang and has a floating nature. Zhang Zhongjing used Guizhi in the *Shanghan Lun* (Treatise on Cold Damage) for sweating to release the exterior when treating cold damage. "Guizhi" refers to the twigs of the cinnamon tree, not the trunk. Its light and thin texture allows it to disperse pathogens. There is now another type called Liugui (Willow Cinnamon), which consists of tender, small cinnamon twigs, particularly suitable for medicines treating the Upper Jiao (Upper Burner). Li Dongyuan stated: Substances with thin qi are Guizhi (Cinnamon Twig); those with dense qi are Rougui (Cinnamon Bark). Thin qi leads to dispersal; Guizhi ascends to release the exterior. Dense qi induces heat; Rougui descends to tonify the Kidney. This follows the natural principle of things tending towards their origins. Hua Shou stated: Guizhi enters the Foot-Taiyang Bladder Meridian; Guixin (Cinnamon Heart) enters the Hand-Shaoyin Heart Meridian blood level; Rougui enters the Foot-Shaoyin Kidney and Foot-Taiyin Spleen Meridians blood level. Thin branches are called Zhi (Twig); tender parts are Zhi; dense fatty parts are Rou (Bark); old parts stripped of bark and inner layer, leaving the center, are Guixin (Cinnamon Heart). Kou Zongshi quoted the *Suwen*: "Acrid and sweet disperse and are Yang." Therefore, Zhang Zhongjing's Guizhi Tang (Cinnamon Twig Decoction) for exterior deficiency in cold damage requires this herb, aligning with the principle of sweet flavors to disperse. Pharmacopoeias exclude Mugui (Mossy Cinnamon) and Jungui (Fungus Cinnamon) because their warmth is insufficient to treat cold-damp conditions. However, the *Shennong Bencao Jing* mentions only Gui (Cinnamon), while Zhang Zhongjing specifies Guizhi, taking the bark from the twigs. Hua Shou addressed a query: The pharmacopoeia states Cinnamon stops irritability and induces sweating. Yet Zhang Zhongjing uses Guizhi Tang multiple times for sweating in cold damage, but also states "no sweat, do not take Guizhi" and "those who sweat excessively should not induce further sweating." Does using Guizhi constitute double sweating? And Guizhi Ganyao Tang (Cinnamon Twig and Licorice Decoction) is used for excessive sweating—does Guizhi stop sweat? Is one herb used oppositely, consistent with pharmacopoeial theory? The answer is: The pharmacopoeia says Cinnamon is acrid, sweet, and greatly hot, guiding other herbs, unblocking vessels, stopping irritability, and inducing sweating by harmonizing blood so sweat emerges naturally. Zhang Zhongjing stated that in Taiyang Wind Strike, Yin weakness causes spontaneous sweating; Wei (Defensive) excess and Ying (Nutritive) deficiency cause fever and sweating. Also, Taiyang disease with fever and sweating indicates Ying weakness and Wei strength, where Yin deficiency allows Yang to encroach. Thus, Guizhi is used to induce sweating by harmonizing Ying Qi, causing Wei Qi to harmonize, leaving no room for wind pathogens, leading to resolution through spontaneous sweating. It is not that Guizhi opens the pores to force sweat. When sweating is excessive, Guizhi is used to harmonize Ying and Wei, allowing pathogens to exit via sweat, thereby stopping sweat; it does not close pore apertures. Ignorant practitioners, misunderstanding the principles of inducing and stopping sweat, use Guizhi for cold damage without sweat, which is a grave error. In Guizhi Tang, the term "induce sweating" should be understood as "sweat emerging naturally," unlike Mahuang (Ephedra) which forcibly opens pores. Treating deficient sweating requires understanding this reverse logic. Cheng Wuji stated: Guizhi primarily resolves muscle tension. If Taiyang Wind Strike presents with tight pores, excess pathogens in Ying and Wei, constricted fluids, floating-tight pulse, fever, and no sweat, this formula is contraindicated. It is indicated only for patients with loose skin, spontaneous sweating, floating-slow pulse, and wind pathogens affecting Wei Qi. Dispersal relies mainly on acrid and sweet flavors. Guizhi is acrid and hot, serving as the Sovereign herb; Shaoyao (Peony Root) as Minister; Gancao (Licorice Root) as Assistant. To counteract excessive wind, use acrid and bitter neutrality, sweet to moderate, and sour to astringe. Ginger and Jujube act as Envoys; their acrid and sweet properties disperse while promoting Spleen-Stomach fluid circulation to harmonize Ying and Wei, rather than solely dispersing. Hence, Mahuang Tang excludes Ginger and Jujube, focusing purely on sweating without needing to circulate fluids. Zhu Danxi stated: Guizhi has light qi and flavor, ascending to disperse at the exterior. For internal cold, Rougui (Cinnamon Bark) tonifies Yang; Liugui is acrid and hot, dispersing channel cold and guiding Yang Qi. For righteous Qi deficiency, use acrid-moistening methods. To disperse cold pathogens and treat Ben Tun (Running Piglet), note that entering the throat with strong Yang can be fatal; it is forbidden in spring and summer. Cinnamon moves blood and is forbidden for blood-heat conditions. Wood dies when encountering Cinnamon; it is forbidden for Liver deficiency. Processing: The toxicity lies in the bark, so it must be peeled before use.

Fuzi (Prepared Aconite Root): The qi is hot, the taste is acrid, with great toxicity. Li Dongyuan stated: Greatly acrid and hot, dense qi and thin flavor, capable of ascending and descending, belonging to Yin within Yang, penetrating all levels (floating, middle, sinking), serving as a guide for various meridians. Hua Shou stated: It enters the Foot-Shaoyin Kidney, Sanjiao (Triple Burner), and Mingmen (Gate of Life) agents. Its nature moves freely and does not stay fixed, unlike Ganjiang (Dried Ginger) which is upright and stationary. Zhao Sizhen stated: Cooked Fuzi paired with Mahuang provides tonification within dispersal, as seen in Zhang Zhongjing's Mahuang Fuzi Xixin Tang (Ephedra, Aconite, and Asarum Decoction) and Mahuang Fuzi Gancao Tang (Ephedra, Aconite, and Licorice Decoction). Raw Fuzi paired with Ganjiang provides dispersal within tonification, as seen in Zhang Zhongjing's Ganjiang Fuzi Tang (Dried Ginger and Aconite Decoction) and Tongmai Sini Tang (Pulse-Recovering Four Reversals Decoction). Lei Xiao stated: All Wutou (Aconite Mother) and Fuzi medicines should be taken cold, employing the method of "treating heat with cold." When Yin-cold is below and Deficient-Yang floats upward, treating with cold increases Yin pathogenicity and worsens the disease. Treating with heat causes rejection and non-absorption. By administering hot medicine cold, the cold body dissipates first, then the hot nature activates, curing the disease without violating its nature, achieving great benefit. This is the subtlety of contrary treatment. Historically, Zhang Zhongjing treated abdominal cold colic with honey-fried Wutou; the *Jin Gui Yao Lue* treated throat bi with honey-roasted Fuzi held in the mouth; Zhu Danxi treated hernia with Wutou and Gardenia, all using heat-for-cold methods. Li Gao treated the nephew of Hanlin Academician Feng with Yin-excess blocking Yang cold damage: red face and eyes, irritability, thirst for drinks, pulse rapid (7-8 beats per breath) but scattering upon pressure. He administered Jiangfu Tang (Ginger and Aconite Decoction) plus Ginseng, half a jin (approx. 300g), resulting in sweating and recovery—a divine efficacy. Wu Kun stated: Fuzi is the essential herb for Yin syndromes. Whenever cold damage transmits to the Three Yin meridians or involves cold damaging the interior (Jia Yin), even if there is high fever with a deep pulse, it must be used. Or in cases of cold extremities, abdominal pain, deep-thin pulse, cyanotic lips, and scrotal retraction, it must be used urgently. It has the power to drive out Yin, restore Yang, and revive the dying. Recently, practitioners hesitate to use Fuzi for Yin-type cold damage due to ambiguity, waiting until Yin is exhausted and Yang fails, which is too late. In Jia Yin cold damage, both interior and exterior Yang and Qi suddenly decline; urgent use of Renshen (Ginseng Root) to strengthen pulses and tonify Yuan Qi, assisted by Fuzi to warm channels and dispel cold, is necessary. Without this, how can one save the patient? Yu Tuan stated: Fuzi possesses a heroic quality and the spirit of breaking through gates. It guides Qi-tonifying herbs through the Twelve Meridians to recover scattered Yuan Yang; guides Blood-tonifying herbs into the Blood level to nourish deficient True Yin; guides Dispersing herbs to open pores and expel exterior wind-cold; guides Warmth herbs to the Lower Jiao to eliminate interior cold-dampness. Regarding Bawei Wan (Eight-Ingredient Pill), the use of Guizhi and Fuzi aims to moisten Kidney dryness with great acridity. Danxi's claim that it removes Dihuang (Rehmannia) stagnation and Haizang's claim that it tonifies Mingmen Minister Fire are incorrect. Process by soaking in child's urine, wrapping in wet paper, baking in ash fire until fragrant like taro, peel navel, slice, and use.

Ganjiang (Dried Ginger): Temperature is warm, taste is acrid, non-toxic. Li Dongyuan stated: Thin qi and dense flavor, semi-floating and semi-sinking, capable of ascending and descending, belonging to Yin within Yang. Greatly acrid and hot, belonging to Yang within Yang. Its functions are fourfold: 1. Enters the Heart to assist Yang; 2. Removes deep-seated cold in organs; 3. Disperses cold in various meridians; 4. Treats cold-induced abdominal pain. For absent Kidney Yang and impending pulse cessation, Black Fuzi serves as a guide, decocted in water, named Jiangfu Tang. It also treats Middle Jiao cold pathogens; when cold dominates, use acrid flavors to disperse. It tonifies the Lower Jiao, hence used in Sini Tang (Four Reversals Decoction). Ganjiang is originally acrid; processed, it becomes slightly bitter, thus staying put rather than moving, making it suitable for interior cold, unlike Fuzi which moves continuously. Lizhong Tang uses it to restore Yang. Li Gao stated: Raw Ganjiang is acrid and processed is bitter, representing Yang. Raw disperses cold pathogens; processed removes stomach cold and stabilizes the center. Excessive use depletes Yuan Qi; acridity disperses, following the principle that "vigorous fire consumes Qi." It must be moderated with raw Gancao. Acrid-hot disperses interior cold; combined with Wuweizi (Schisandra Fruit) to warm the Lung; combined with Renshen to warm the Stomach. Hua Shou stated: Ganjiang is a Qi-level herb for the Heart and Spleen meridians, thus tonifying Heart Qi deficiency. Some say Ganjiang is acrid-hot yet described as tonifying the Spleen; why does Lizhong Tang speak of draining rather than tonifying? Because acrid-hot dries dampness, draining Cold-Damp pathogens from the Spleen, not draining righteous Qi. White, firm, and solid specimens are superior; processing is recommended.

Shengjiang (Fresh Ginger): Temperature is slightly warm, taste is acrid, qi and flavor are dense, floating and ascending, belonging to Yang, non-toxic. Cheng Wuji stated: Ginger and Jujube have acrid-sweet flavors, specifically circulating Spleen fluids to harmonize Ying and Wei, not solely for dispersal in medicinal formulas. Li Gao stated: Fresh Ginger has four uses: 1. Mitigates toxicity of Banxia (Pinellia Rhizome) and Houpo (Magnolia Bark); 2. Disperses wind-cold; 3. Combined with Jujube, acrid-warm tonifies Spleen-Stomach Yuan Qi, warms the center, and drains dampness; 4. Combined with Shaoyao, warms channels and disperses cold. Sun Simiao said: Ginger is the sage medicine for vomiting. Acridity disperses; vomiting results from stagnant Qi, which ginger disperses by moving Yang and scattering Qi. Query: Fresh Ginger is acrid-warm and enters the Lung; why is it said to enter the Stomach opening? Answer: Popular belief places the Stomach opening below the heart, which is incorrect. Below the pharynx, receiving solid food and connecting to the Stomach system is the Stomach opening. Since it travels with the Lung system, it enters the Lung and opens the Stomach. Query: People say eating Ginger at night closes Qi. Answer: Ginger is acrid-warm and promotes development/opening. At night, Qi naturally converges; forcing it open violates Heavenly Dao. However, for patients, this rule does not apply. Ginger powder is less hot than Ganjiang and less moist than Shengjiang. Dried Ginger can substitute for Ganjiang because it is not overly aggressive. Folk saying: Eat radish in bed, eat ginger out of bed. Ginger opens the appetite; radish aids digestion. Use peeled Ginger for heat; keep skin for cold.

Wuzhuyu (Evodia Fruit): Temperature is warm, taste is acrid, slight toxicity. Hua Shou stated: Acrid-bitter and hot, dense qi and flavor, Yin within Yang, semi-floating and semi-sinking. Enters Foot-Taiyin Spleen Meridian blood level, and Foot-Shaoyin Kidney and Foot-Jueyin Liver Meridian Qi level. Li Dongyuan stated: Its uses are three: removes rebellious Qi and fullness in the chest, stops cold-induced abdominal pain, eliminates residual alcohol, and acts as an assistant to Bai Doukou (Cardamom Seed). Li Gao stated: Treats cold in the throat causing obstruction in the chest. Classics state dysphagia and inability to swallow lead to vomiting, staring eyes, and closed mouth due to cold pathogen accumulation preventing Qi movement up and down. If untreated, it causes interior cold, abdominal distension, and diarrhea. Use Wuzhuyu's bitter-hot nature to drain rebellious Qi; it works miraculously,不可替代 by other herbs. Hua Shou stated: When the Wei Pulse is diseased, causing rebellious Qi and interior urgency, this herb is primary. Green color corresponds to Zhen and Kun trigrams. Thus, Zhang Zhongjing's Wuzhuyu Tang (Evodia Decoction) and Danggui Sini Tang (Angelica Decoction for Cold Extremities) use it for Jueyin diseases and warming Spleen-Stomach. Wash soup to remove bitterness, sun-dry, and crush.

Shu Jiao (Sichuan Pepper): Temperature is warm, taste is acrid, toxic. Primarily treats evil Qi, warms the middle, removes cold-bi, strengthens teeth, brightens eyes, and benefits the Five Viscera. Dai Yuanli stated: When patients vomit and cannot retain medicine, there are likely roundworms in the diaphragm. Worms move upon smelling medicine, causing the medicine to exit while worms remain. Adding ten fried Sichuan Peppers to anti-vomit medicine is effective because worms lower their heads upon seeing pepper. This explains why Zhang Zhongjing uses Shu Jiao in Wumei Wan (Mume Pill) for Huijue (Roundworm Convulsion). Xu Yishi stated: Generally, when Kidney Qi rebels upward, Sichuan Pepper guides it back to its meridian, ensuring stability. Remove eyes and closed pods, fry to remove moisture, rub finely by hand.

Badou (Croton Seed): Temperature is warm, taste is acrid, great toxicity. Li Dongyuan stated: Thin qi and dense flavor, heavy weight and sinking, belonging to Yin. Hot nature and acrid taste, great toxicity, floating, belonging to Yang within Yang. Li Dongyuan also stated: It is a general who breaks through gates; do not use lightly. Hua Shou stated: For acute treatment, it acts as a purgative for food and water pathways; use raw, peeled, seedless, oil-free. For chronic treatment, it dissolves hardness and grinds accumulations; fry until smoke disappears and turns purple-black. It can unblock intestines or stop diarrhea, a secret unknown to the world. Zhang Zhongjing used it in Beijie Wan (Emergency Rescue Pill) for various diseases and Ke Wu (Guest Spirit Invasion).

Houpo (Magnolia Bark): Temperature is warm, taste is bitter and acrid, non-toxic. Heavy vapor and flavor, heavy and turbid, slightly sinking, belonging to Yin within Yang. Li Gao stated: Capable of ascending and descending, removing abdominal distension. Even if weak patients have distension, use with caution; this applies to cold distension. Used alongside greatly hot medicines, it is a divine drug for dispersing knots. Misuse depletes righteous Qi; strictly prohibited. Hua Shou stated: Pharmacopoeia claims Houpo treats wind-stroke, cold damage headache, warms middle, tonifies Qi, resolves phlegm, directs Qi downward, thickens intestines, and removes abdominal fullness. Does it drain Qi or tonify Qi? When combined with Zhishi (Immature Bitter Orange) and Dahuang (Rhubarb Root), it drains excess fullness, known as resolving phlegm and directing Qi downward. When combined with Chenpi (Tangerine Peel) and Cangzhu (Atractylodes Rhizome), it drains dampness fullness, known as warming the middle and tonifying Qi. Combined with relieving medicines, it treats cold damage headache; combined with diarrhea medicines, it thickens intestines. Generally, its nature is bitter-warm; bitter drains, warm tonifies. Thus, Cheng Shi stated: Houpo's bitterness drains abdominal fullness; since it directs Qi downward, it drains excess fullness; its warmth tonifies Qi, thus dispersing dampness fullness. Peel, chop, soak in Ginger Juice, stir-fry lightly, and sieve uniformly.