桂枝四两 甘草（炙）二两
右二味，以水三升煮取一升，去滓，顿服。
【集解】
柯琴曰：汗出多，则心液虚，中气馁，故悸。叉手自冒，则外有所卫，得按，则内有
所根据，如此不堪之状，望之而知其为虚矣。桂枝本荣分药，得麻黄则今荣气外发而为
汗，从辛也；得芍药则收敛荣气而止汗，从酸也；得甘草则补中气而养血，从甘也。
故此方以桂枝为君，独任甘草为佐，以补阳气，生心液，甘温相得，斯气血和而悸自
平。不须附子者，以汗虽多，而未至于亡阳；不须芍药者，以汗已止，而嫌其敛阴也
。
发汗后，其人脐下悸者，欲作奔豚，茯苓桂枝甘草大枣汤主之。
【注】
发汗后心下悸者，乃虚其心中之阳，本经自病也。今发汗后，脐下悸，欲作奔豚者，
乃心阳虚，而肾水之阴邪，乘虚欲上干于心也。主之以茯苓桂枝甘草大枣汤者，一以
扶阳，一以补土，使水邪不致上干，则脐下之悸可安矣。
【集注】
程知曰：发汗后心下悸者，心液虚而肾气将动也，肾气欲上奔，故脐下先悸也。谓之
豚者，指肾气也。
喻昌曰：汗本心之液，发汗后脐下悸者，心气虚而肾气发动也。故取茯苓桂枝直趋肾
界，预伐其邪，所谓上兵伐谋也。
汪琥曰：奔豚者，肾之积名也。发于少腹，上至心下，若豚状，乃肾气发动，有似乎
奔豚之状，非真脐下有积如豚也。
Cinnamon Twig (Guizhi) four liang, Licorice Root (Gancao) [roasted] two liang.
These two ingredients are boiled in three sheng of water until one sheng remains. The dregs are strained out, and the decoction is taken in one dose.
[Collected Explanations]
Ke Qin stated: Profuse sweating depletes Heart fluid (Xin Ye), weakening the Middle Qi, thus causing palpitations (Ji). Crossing hands over the chest provides external protection; receiving pressure offers internal support. Such unbearable symptoms clearly indicate a deficiency pattern upon observation. Cinnamon Twig (Guizhi) is primarily a herb for the Ying (Nutritive) level. When combined with Ephedra Herb (Mahuang), it directs Ying Qi outward to induce sweating, utilizing its acrid (Xin) property. When combined with White Peony Root (Shaoyao), it consolidates Ying Qi and stops sweating, utilizing its sour (Suan) property. When combined with Licorice Root (Gancao), it tonifies Middle Qi and nourishes blood, utilizing its sweet (Gan) property. Therefore, this formula uses Cinnamon Twig (Guizhi) as the Sovereign herb, with Licorice Root (Gancao) alone serving as an Assistant, to tonify Yang Qi and generate Heart fluid. The harmony of sweet and warm properties harmonizes Qi and Blood, allowing palpitations to subside naturally. Aconite Root (Fuzi) is not needed because, although sweating is profuse, it has not yet reached the stage of Yang collapse (Wang Yang). White Peony Root (Shaoyao) is not needed because sweating has ceased, and its Yin-consolidating effect is undesirable.
After inducing sweating, if the patient experiences palpitations below the umbilicus, indicating an impending Ben Tun (Rushing Pig syndrome, characterized by a sensation of Qi rushing upward from the lower abdomen), Poria cocos, Cinnamon Twig, Licorice Root, and Jujube Decoction (Fuling Guizhi Gancao Dazao Tang) should be administered.
[Annotation]
Palpitations in the epigastrium after sweating result from deficiency of Heart Yang, representing a disease of the meridian itself. In contrast, palpitations below the umbilicus after sweating, indicating impending Ben Tun, result from Heart Yang deficiency, allowing Yin pathogenic factors from Kidney Water to invade the Heart due to the void. Poria cocos, Cinnamon Twig, Licorice Root, and Jujube Decoction (Fuling Guizhi Gancao Dazao Tang) is used to support Yang and tonify Earth (Spleen/Stomach), preventing Water pathogens from invading upward, thereby calming palpitations below the umbilicus.
[Collected Notes]
Cheng Zhi stated: Palpitations in the epigastrium after sweating indicate depleted Heart fluid and stirring Kidney Qi. As Kidney Qi attempts to rush upward, palpitations occur first below the umbilicus. The term "Tun" (pig) refers to Kidney Qi.
Yu Chang stated: Sweat is the fluid of the Heart. Palpitations below the umbilicus after sweating indicate deficient Heart Qi and stirring Kidney Qi. Therefore, Poria cocos and Cinnamon Twig are selected to act directly on the Kidney region to preemptively suppress the pathogen, which aligns with the principle of "the best strategy is to attack the enemy's plans."
Wang Hu stated: Ben Tun is the name of a Kidney accumulation disease. It originates in the lower abdomen and ascends to the epigastrium, resembling a running pig. This represents the stirring of Kidney Qi, appearing similar to Ben Tun symptoms, rather than an actual mass resembling a pig below the umbilicus.