【Source】

《Shanghan Lun, Jingui Yaolue》

 【Composition】

Gegen (Kudzu Root), Mahuang (Ephedra Herb), Guizhi (Cinnamon Twig), Shaoyao (Peony Root), (炙)Gancao (Prepared Licorice Root), Shengjiang (Fresh Ginger), Dazao (Jujube)
(7 ingredients)

 【Categorization of Ingredients】

<Blood Tonifying>: Shaoyao (Peony Root)

<Spleen & Middle Jiao Tonifying>: Dazao (Jujube), Gancao (Licorice Root)

<Acrid-Cool Exterior-Releasing>: Gegen (Kudzu Root)

<Acrid-Warm Exterior-Releasing>: Guizhi (Cinnamon Twig), Shengjiang (Fresh Ginger), Mahuang (Ephedra Herb)

【Formula Explanation】

《Yifang》: For Taiyang channel disorders. Cheng Shi said: “Light substances can remove excess; Gegen and Mahuang are examples. This formula is used for *Zhongfeng* (wind-stroke) with exterior excess, hence these two ingredients are added to Guizhi Tang.” 《Shanbu》: This formula is Guizhi Tang with the addition of Mahuang and Gegen. Mahuang assists Guizhi in inducing perspiration from the Taiyang Ying-Wei (nutritive and defensive qi).

Gegen acts as the chief herb, with Guizhi as assistant, to resolve pathogenic factors from the Yangming muscle and exterior. It is not named “Guizhi Tang with Mahuang and Gegen” but rather “Gegen Tang,” indicating its emphasis on Yangming disorders, as vomiting and diarrhea are often associated with Yangming.

When both Taiyang and Yangming exterior are acute, inducing sweating by warming and covering is necessary, otherwise the exterior cannot be easily resolved. If there is vomiting or diarrhea, the interior is already unbalanced. Even if congee is consumed, the stomach cannot transport essences to the skin and hair, hence congee is not required.

Ke Qin said: “In this condition, there is no pain in the body, lower back, or joints, and no aversion to cold, indicating the bones are not affected by cold. The severe pain and stiffness in the head and neck, extending to the back, causing discomfort, indicate the tendons are injured by wind. No wheezing, irritability, or dry heaving means the interior is not diseased. With anhidrosis and aversion to wind, the disease is solely in the exterior. If there is exterior disease combined with diarrhea, it is exterior excess with interior deficiency. This condition is milder than Mahuang Tang and Daqinglong Tang.

However, the severe stiffness and rigidity of the neck extending to the back are even more pronounced than neck stiffness with anhidrosis, but it remains an exterior condition. Since the pulse is floating but not tense, it does not follow Mahuang Tang. Instead, Mahuang and a double dose of Gegen are added to Guizhi Tang to resolve the excess, which is a slight modification of the Mahuang and Guizhi method. Gegen is the primary herb for the Yangming channel. Whenever Taiyang involves Yangming, Gegen can be added to Taiyang formulas; whenever Shaoyang involves Yangming, it can be added to Shaoyang formulas. Li Gao classified it as a Yangming channel herb.

Zhang Jiegu said: ‘It should not be taken before the disease enters Yangming.’ Had these two not read Zhang Zhongjing’s books? It is important to know that Gegen and Guizhi are both herbs that resolve muscle tension and harmonize the interior. Therefore, they can be used whether there is sweating or anhidrosis, diarrhea or no diarrhea, unlike Mahuang which is solely for releasing the exterior.” 《Jingui Yaolue》: Treats Taiyang disease with anhidrosis, scanty urination, qi rushing upward to the chest, locked jaw and inability to speak, and impending rigid spasm.

《Jizhu》: Yu Chang said: “For cold damage with severe stiffness of the neck and back, anhidrosis, and aversion to wind, use Gegen Tang.” This formula is also used for this condition because the pathogenic factor is at the junction of the Taiyang and Yangming channels. The heat from both channels converges in the chest, inevitably impairing the clear descending function of the lung qi, thus obstructing water passages, leading to scanty urination, and the failure of body fluids to be distributed, resulting in anhidrosis. The tendons of the Yangming channel are internally connected to the stomach opening, externally travel through the chest, and pass through the Renying (Carotid artery) and around the mouth.

When heat converges in Yangming, the tendons and vessels are constricted, causing locked jaw and inability to speak. However, rigid spasm with anhidrosis must be resolved by sweating, and furthermore, internal dampness obstruction must be resolved by sweating until the original state is restored. Therefore, this decoction is used to resolve the damp-heat of both channels, along with the exterior wind-cold. The principle is not contradictory. 《Handian》: This formula is a modification of Guizhi Tang with the addition of Mahuang and Gegen. It is used to relieve excessive muscle tension, dilate blood vessels, promote blood circulation, and has diaphoretic and diuretic effects.

 【Functions】

Induces sweating to relieve muscle tension, disperses cold, generates fluids to relax tendons, and harmonizes the exterior and interior.

 【Indications】

(1) For exterior wind-cold invasion, *Shanghan* exterior excess, headache, stiffness of the neck and back, body pain, fever with aversion to cold, anhidrosis; or for Taiyang disease with anhidrosis and scanty urination, qi rushing upward to the chest, counterflow qi leading to chest fullness, locked jaw and inability to speak, impending rigid spasm; or for wind-cold exterior excess combined with interior pathogenic factors causing diarrhea. (2) This is a well-known remedy for the common cold, but its use is not limited to colds.

It can be used regardless of whether there is fever and aversion to cold, as long as the pulse is floating and forceful, and there is tension in the neck and back. 《Yifang》:

(1) Treats Taiyang disease with severe stiffness of the neck and back, anhidrosis, and aversion to wind (*Shanghan Lun, Chapter on Combined Diseases*).

(2) Also treats Taiyang-Yangming combined disease with diarrhea (*Shanghan Lun, Chapter on Combined Diseases*). 《Shanbu》: For combined Taiyang and Yangming channel diseases with severe headache and neck stiffness, back rigidity, floating pulse, anhidrosis, and aversion to wind; and for cases where the exterior is not resolved, with diarrhea and vomiting. In all these cases, inducing sweating with this formula is appropriate.

 【Applications】

(1) Common cold, influenza, upper respiratory tract infection, epidemic encephalitis, Japanese encephalitis, acute gastroenteritis, dysentery, infantile autumn diarrhea with fever, skin infections, cervical spondylosis, neuromuscular diseases, urticaria, etc. (2) Conjunctivitis, keratitis, otitis media, otitis externa, rhinitis, sinusitis, stiff shoulders, frozen shoulder (adhesive capsulitis), neuralgia, etc. Therefore, this formula can be applied to conditions such as colds, flu, colitis, dysentery, urticaria, and others.

 【Contraindications】

(1) Contraindicated for exterior deficiency patterns due to external wind-cold invasion. (2) Should be avoided in the initial stage of warm-febrile diseases with severe fever, mild aversion to cold, thirst, floating-rapid pulse, and red tongue tip and edges. (3) Contraindicated for those with sweating and aversion to wind. (4) For individuals with weak stomach and spleen or muscle flaccidity, using this formula may lead to feelings of exhaustion and decreased appetite.

 【Mnemonic】

Guizhi Tang (Guizhi, Shaoyao, Gancao, Dazao, Shengjiang – “Gui Sao San Zuo”) + Mom’s Older Brother (Mahuang, Gegen – “Mama de Gege”).

 【Modifications】

《Handian》: Gegen Jia Banxia Tang (Kudzu Decoction plus Pinellia) is used for Gegen Tang patterns with vomiting and nausea.

 【Pharmacology】

Antipyretic, antimicrobial, antiallergic, immune-enhancing, cerebral vasodilator, inhibits thrombus formation. It has a significant effect on dilating cerebral blood vessels, increasing cerebral blood flow, and reducing cerebral vascular resistance in anesthetized dogs and cats. Additionally, it counteracts ADP-induced platelet aggregation in rabbits.