气味甘平。生则微凉。味不佳。炙则温。气薄味浓。可升可降。阴中阳也。入足
太阴厥阴。通入手足十二经。术苦参干漆为之使。恶远志。反大戟芫花甘遂海藻。
主治和诸药。（热药得之缓其热。寒药得之缓其寒。寒热相杂用之得其平。）补正气。解
诸味及百药毒。（诸毒遇土则化。甘草为土精。故能化毒。解一切邪气。）生用泻心火及诸火
热。（分身梢用）熟用补三焦元气。散表寒。除邪热。去咽痛。缓正气。养阴血。（补伤寒瘥
后血虚）补脾胃。润肺。吐肺痿之脓血。消五发之疮疽（海藏）甘而缓。故能泻热而补阳。
甘缓善解诸急。故即舒阳以裕阴。所由治诸经急痛。凡心火乘脾。腹中急痛。腹皮急缩者。
宜倍用之。甘温能除大热。（凡阳虚之热宜甘温。阴虚之火则宜甘寒。两者或误。去之远矣。
东垣用甘温以缓正气。养阴血。的为精诣。误者用以疗阴虚血衰。失之远矣。）五味之用。
苦泄。辛散。酸收。咸润下而敛。甘上行而发。而本草言甘草下气。何也。盖甘味入中。有
升降浮沉。可上可下。可外可内。有和有缓。有补有泻。居中之道尽矣。仲景附子理中汤用
甘草。恐其僭上也。调胃承气用甘草。恐其速下也。此缓之之意。小柴胡有柴芩之寒。参半
之温。用甘草和之。建中汤用之以补中而缓脾急。凤髓丹用之以缓肾急而生元气。乃甘补之
意。
（泻火义自明）又能引诸药直至病所。以甘味入脾。归其所喜。此升降浮沉之理。（海藏）
中乌头巴豆毒。甘草入腹即定。古称大豆汁解百药毒。试之每不效。加入甘草为甘豆汤。其
验乃奇。（千金）此方亦救中砒毒者。佐黄 防风能运毒走表。为痘疹气血两虚者。首尾必
资之剂。得白芍则补脾。甲己化土故也。同人参黄 白术当归大枣麦冬。加升麻柴胡。为补
中益气药。专理饥饱劳役。内伤阳气下陷发热。同人参干姜肉桂则温中。同麦冬苏子枇杷叶
则下气。同黄连芍药升麻滑石。解热毒滞下。同桔梗元参大力子栝蒌根。清利咽喉虚热。同
人参菖蒲益智远志龙眼肉治健忘。同麦冬石膏知母竹叶。除烦闷燥渴。头疼解肌。同黄连木
通赤芍生地。泻心经有余之火。同预知子贯众。解一切蛊毒。
附方 肺痿吐涎沫头眩。小便数而不咳者。其人不渴。肺中冷也。甘草干姜汤温之。炙
草四两。炮干姜二两。水三升。煮一升五合。分服。肺痿久嗽。涕唾多。骨节烦闷。寒热以
炙甘草三两捣为末。每日取小便三合。调末一钱服之。
〔论〕 甘草独以甘擅名。别录谓其为九土之精。能治七十二种乳石毒。解千二百般草
木毒。是一和足以概众美矣。第就和之中。其功有缓。而缓之中。其功又有泻。就缓泻之中。
其功更有补也。东垣云。脾胃不足而心火乘脾。火性苦急。赖此缓之。此火非可以苦寒泻。
即以甘平而和缓者泻之。（后天阳气之原出于胃。虽土以火为母。而心火更以土为化原。脾
胃虚则心火之化原绝。故母反索救于子以乘脾也。心火乘脾。阳不能生阴而反厉阴。惟甘温
能缓正气。即以养阴血。是又可通于养心血之义矣。）一炙则为甘温。即以补阳之不足矣。
梢
生者治胸中积热。去茎中痛。加酒煮元胡索苦楝子尤妙。（元素）用于下焦宜梢子者。
缘概用恐太缓。不能达也。
头
生者能行足厥阴阳明污浊血。消肿导毒。（丹溪）宜入吐药。（濒湖）
缪氏云。中满者忌之。呕家酒家诸湿肿满及胀满。咸不宜服。诸解利药中。宜少用。恐
缓而少效。即补药中。亦不宜多用。恐恋膈不思食。脾虚者固宜用之。若脾胃气有余。与痢
疾初起。皆不可用。（嵩）
〔修治〕 大至径寸而结紧。横有断纹者佳。炙者用长流水蘸湿频烤至熟。刮去赤皮。
气味：味甘，性平。生用则微凉，味道不佳；炙用则性温，气薄味浓，具有升浮和沉降的双重特性，属于阴中寓阳之品。
归经与配伍：入足太阴脾经、足厥阴肝经，通行手足十二经脉。以白术、苦参、干漆为引药（使药）。忌与远志同用。与大戟、芫花、甘遂、海藻相反（十八反禁忌）。
主治功效：
1. 调和诸药：热药得甘草则其热性减缓，寒药得甘草则其寒性缓和，寒热药物杂用时，借甘草之力达到平衡。
2. 补益正气，解百毒：各种毒素遇到土气则化解，甘草为“土精”，故能化解毒素，解除一切邪气。
3. 生用功效：清泻心火及各类火热证。（使用时区分部位，如梢部）
4. 熟用（炙用）功效：补益三焦元气，发散表寒，清除邪热，缓解咽喉疼痛，缓和正气，滋养阴血。（适用于伤寒病愈后血虚之证）
5. 补脾胃，润肺：治疗肺痿吐出的脓血，消除五种因发热引起的疮疽（据海藏观点）。
6. 缓急止痛：甘草味甘且缓，故能泻热而补阳。甘缓之性能解除各种急症，从而舒展阳气以充裕阴液。因此用于治疗各经的急痛。凡是心火乘袭脾土，导致腹中急痛、腹部皮肤紧缩者，宜加倍使用。
7. 甘温除大热：凡属阳虚产生的热象，宜用甘温之法；阴虚产生的火旺，则宜用甘寒之法。两者若误用，后果相差甚远。李东垣用甘温之法来缓和正气、滋养阴血，可谓精辟独到。若误用于阴虚血衰之证，则谬以千里。
8. 五味理论辨析：苦味主泄，辛味主散，酸味主收，咸味主润下而收敛，甘味主上行而发散。但《本草》言甘草能“下气”，这是为什么呢？因为甘味入中焦，具有升降浮沉的特性，可上可下，可外可内，有和有缓，有补有泻，体现了居中调和的道理。
9. 方剂应用解析：
- 张仲景在附子理中汤中使用甘草，是担心药力僭越上行；
- 在调胃承气汤中使用甘草，是担心泻下过快；
- 这体现了“缓”的意图。
- 小柴胡汤中有柴胡、黄芩之寒，人参、半夏之温，用甘草来调和；
- 建中汤用甘草来补中焦并缓和脾之急迫；
- 凤髓丹用甘草来缓和肾之急迫并生发元气；
- 这体现了“甘补”的意图。（泻火的含义自明）
10. 引经报使：又能引导诸药直达病所，因为甘味入脾，归于其所喜之处，此乃升降浮沉之理。（据海藏观点）
11. 解毒特效：中乌头、巴豆毒时，甘草入腹即能定毒。古称大豆汁能解百药毒，但尝试往往无效。加入甘草制成甘豆汤，疗效奇特。（据《千金方》）此方也能解救砒霜中毒。
12. 配伍变化：
- 佐以黄芪、防风，能运化毒邪至体表，是痘疹气血两虚者首尾必用的药剂。
- 得白芍则补脾，因甲己化土之故。
- 同人参、黄芪、白术、当归、大枣、麦冬，加升麻、柴胡，组成补中益气药，专门调理饥饱劳役导致的内伤阳气下陷发热。
- 同人参、干姜、肉桂则温中。
- 同麦冬、苏子、枇杷叶则降气。
- 同黄连、芍药、升麻、滑石，解热毒及痢疾。
- 同桔梗、玄参、牛蒡子、瓜蒌根，清利咽喉虚热。
- 同人参、石菖蒲、益智仁、远志、龙眼肉，治疗健忘。
- 同麦冬、石膏、知母、竹叶，除烦闷燥渴，治头疼解肌。
- 同黄连、木通、赤芍、生地，泻心经有余之火。
- 同预知子、贯众，解一切蛊毒。
附方：
1. 肺痿吐涎沫、头眩、小便频数而不咳、口不渴者，此为肺中寒冷。用甘草干姜汤温之。炙甘草四两，炮干姜二两，水三升，煮取一升五合，分次服用。
2. 肺痿久嗽、涕唾多、骨节烦闷、寒热往来者，用炙甘草三两捣为末，每日取小便三合，调服药末一钱。
〔论〕
甘草独以“甘”味擅名。《别录》谓其为九土之精，能治七十二种乳石毒，解千二百般草木毒，一言以蔽之，“和”字足以概括其众美。但在“和”之中，其功效有“缓”；在“缓”之中，其功效又有“泻”；在“缓”和“泻”之中，其功效更有“补”。
李东垣云：脾胃不足而心火乘脾，火性苦急，赖甘草之甘缓以制之。此火不可用苦寒直泻，即以甘平之性而和缓之即可泻之。（后天阳气之源出于胃，虽土以火为母，而心火更以土为化原。脾胃虚则心火之化原绝，故母反求救于子以乘脾也。心火乘脾，阳不能生阴而反厉阴，惟甘温能缓正气，即以养阴血，此义又可通于养心血之义矣。）
一旦炙过，则变为甘温，用以补阳气之不足。
梢：生用治胸中积热，去茎中痛，加酒煮延胡索、苦楝子尤妙。（据元素观点）用于下焦宜用梢子，因为概用全草恐药力太缓，不能达于下焦。
头：生用能行足厥阴、阳明经之污浊血，消肿导毒。（据丹溪观点）宜入吐药。（据濒湖观点）
缪氏云：中满者忌用。呕家、酒客、诸湿肿满及胀满者，均不宜服用。在诸解利药中，宜少用，恐药性缓而少效。即在补药中，亦不宜多用，恐恋膈碍胃不思食。脾虚者固宜用之，若脾胃气有余，或痢疾初起，皆不可用。（据嵩观点）
〔修治〕
直径一寸以上且结紧实、横有断纹者为佳。炙法：用长流水蘸湿，频频烘烤至熟透，刮去赤皮。
Odor and Flavor: Sweet in flavor, neutral in nature. When raw, it is slightly cool and has an inferior taste; when honey-fried (Zhi), it becomes warm, with a thin odor and strong flavor. It possesses both ascending/descending properties and belongs to the category of "Yang within Yin."
Meridian Tropism and Compatibility: Enters the Foot-Taiyin Spleen Meridian and Foot-Jueyin Liver Meridian, and communicates through all twelve meridians of the hands and feet. Its guiding herbs (Shi) include Atractylodis Rhizoma (Baizhu), Sophorae Flavescentis Radix (Kushen), and Drynariae Rhizoma? No, Ganji (Ganji). It is incompatible with Hedysari Radix? No, Yuanzhi. It is chemically antagonistic (Eighteen Incompatibilities) with Euphorbiae Pekinensis Radix (Daji), Genkwa Flos (Yuanhua), Kansui Radix (Gansui), and Sargassum (Haizao).
Indications and Functions:
1. Harmonizing other herbs: When combined with hot herbs, its heat is moderated; when combined with cold herbs, its coldness is moderated. When mixed with both hot and cold herbs, Gancao achieves balance.
2. Tonifying righteous Qi and resolving toxins: Toxins are transformed by Earth energy. As the "essence of Earth," Gancao can resolve toxins and dispel all pathogenic factors.
3. Raw usage: Clears Heart Fire and various types of heat syndromes. (Differentiate usage by part, e.g., tips.)
4. Fried (cooked) usage: Tonifies the Yuan Qi of the Sanjiao, disperses exterior cold, eliminates pathogenic heat, relieves sore throat, moderates righteous Qi, and nourishes Yin blood. (Applicable to blood deficiency after recovery from Shanghan/Exogenous Febrile Disease.)
5. Tonifying Spleen and Stomach, moistening Lungs: Treats pus and blood expectorated in Fei Wei (Lung Atrophy); resolves sores and carbuncles arising from five types of heat (according to Haicang).
6. Relieving urgency and pain: Due to its sweet and moderating nature, it clears heat and tonifies Yang. Its sweet moderation resolves various acute conditions, thereby soothing Yang to enrich Yin. Thus, it treats urgent pain in various meridians. In cases where Heart Fire overacts on Spleen Earth, causing abdominal urgency/pain and skin contraction, the dosage should be doubled.
7. Sweet-Warm method for Great Heat: For heat caused by Yang deficiency, the sweet-warm method is appropriate; for fire caused by Yin deficiency, the sweet-cold method is appropriate. Misapplication leads to significant error. Li Dongyuan’s use of sweet-warm methods to moderate Qi and nourish Yin blood is profound. Misusing this for Yin deficiency and blood depletion is a grave mistake.
8. Analysis of Five Flavors: Bitter drains, Pungent disperses, Sour astringes, Saline moistens and descends/astringes, Sweet ascends and disperses. However, Materia Medica states Gancao "descends Qi." Why? Because Sweet flavor enters the Middle Jiao, possessing ascending/descending and floating/sinking dynamics. It can go up or down, out or in, harmonize or moderate, tonify or drain, embodying the Dao of the Center.
9. Formula Applications:
- Zhang Zhongjing uses Gancao in Fuzi Lizhong Tang to prevent rebellious upward movement.
- He uses it in Tiaowei Chengqi Tang to prevent rapid purgation.
- This reflects the intent of "moderation."
- In Xiaochaihu Tang, containing Chaihu/Huangqin (cold) and Renshen/Banxia (warm), Gancao is used to harmonize.
- In Jianzhong Tang, it tonifies the Middle and moderates Spleen urgency.
- In Fengsui Dan, it moderates Kidney urgency and generates Yuan Qi.
- This reflects the intent of "Sweet Tonification." (The meaning of draining fire is self-evident.)
10. Guiding Action: It guides other herbs directly to the disease site because Sweet flavor enters the Spleen, returning to its preferred organ, illustrating the principles of ascending/descending and floating/sinking. (According to Haicang.)
11. Antidote Effectiveness: For poisoning by Aconitum (Wutou) or Croton (Badou), Gancao settles the toxin upon entering the abdomen. Ancient texts claim Soybean Decoction resolves all herb toxins, but trials often fail. Adding Gancao to create Gandou Tang yields miraculous results. (According to Qianjin Fang.) This formula also rescues Arsenic poisoning.
12. Compatibility Variations:
- With Huangqi and Fangfeng, it transports toxins to the exterior; it is essential for acne/rash patients with Qi and Blood deficiency.
- With Baishao, it tonifies the Spleen due to the transformation of Wood and Earth (Jia-Ji).
- With Renshen, Huangqi, Baizhu, Danggui, Dazao, Maidong, plus Shengma and Chaihu, it forms Bu Zhong Yi Qi formulas, specifically treating internal injury from hunger/fatigue leading to sinking of Yang Qi and fever.
- With Renshen, Ganjiang, Rougui, it warms the Middle.
- With Maidong, Suzi, Pipayexie, it directs Qi downward.
- With Huanglian, Shaoyao, Shengma, Huashi, it resolves heat toxins and dysentery.
- With Jiegeng, Xuanshen, Niubangzi, Gualuagen, it clears and benefits the throat for deficient heat.
- With Renshen, Changpu, Yizhiren, Yuanzhi, Longyanrou, it treats forgetfulness.
- With Maidong, Shigao, Zhimu, Zhuyexie, it relieves restlessness, dryness, and thirst, treating headache and releasing the muscle layer.
- With Huanglian, Mutong, Chishao, Shengdi, it drains excess fire from the Heart channel.
- With Yuzhizi and Guanzhong, it resolves all gu toxins.
Attached Formulas:
1. For Lung Atrophy with saliva expectoration, dizziness, frequent urination without cough, and no thirst (indicating Cold in the Lung): Use Gancao Ganjiang Tang to warm. Honey-fried Gancao 4 liang, Pao Ganjiang 2 liang. Boil in 3 sheng of water to obtain 1.5 sheng. Divide and take.
2. For chronic cough in Lung Atrophy, excessive sputum, bone/joint irritability, and alternating chills/fever: Use 3 liang of honey-fried Gancao, pounded to powder. Take 1 qian daily mixed with 3 he of urine.
[Discussion]
Gancao is famous primarily for its sweetness. The Bencao Jing Bie Lu calls it the "essence of nine soils," capable of treating seventy-two types of mineral poison and resolving thousands of plant poisons. One word, "Harmonizing," summarizes its virtues. Within "Harmonizing," there is "Moderation"; within "Moderation," there is "Draining"; and within "Moderation" and "Draining," there is "Tonification."
Li Dongyuan stated: When Spleen/Stomach are deficient and Heart Fire overacts on Spleen, the fire's bitter-urgency requires moderation by Gancao. This fire cannot be drained by bitter-cold; rather, it is drained by its sweet-neutral moderating nature. (Postnatal Yang originates from the Stomach. Although Earth is the mother of Fire, Heart Fire relies on Earth for transformation. Spleen/Stomach deficiency cuts off this source, causing Mother to seek help from Child, leading to overaction. Heart Fire overacting on Spleen prevents Yang from generating Yin and instead harasses Yin. Only Sweet-Warm can moderate Righteous Qi and thus nourish Yin blood, which aligns with nourishing Heart Blood.)
Once fried, it becomes Sweet-Warm, tonifying insufficient Yang.
Tips (Shao): Raw tips treat accumulated heat in the chest and penile pain. Adding wine-boiled Yanhusuo and Kulianzi is excellent. (According to Yuanyu) For Lower Jiao issues, tips are preferred because using the whole root may be too slow to reach the destination.
Head (Tou): Raw head moves turbid blood in Foot-Jueyin and Foot-Yangming meridians, reduces swelling, and guides out toxins. (According to Danxi) Suitable for emetic formulas. (According to Binhu)
Miao Shi said: Contraindicated in fullness of the Middle Jiao. Not suitable for those with vomiting, alcohol consumption, dampness, edema, or distension. In detoxifying formulas, use sparingly to avoid ineffectiveness due to slowness. Even in tonics, do not use excessively to avoid stagnation in the chest and loss of appetite. Suitable for Spleen deficiency, but contraindicated if Spleen/Stomach Qi is abundant or at the onset of dysentery. (According to Song)
[Processing]
Roots with a diameter of one cun or more, tight knots, and transverse wrinkles are superior. Processing for frying: Moisten with long-flowing water, roast frequently until cooked, and scrape off the red skin.