太阴之证，不必皆由少阳传来也，又间有自太阳传来者。然自少阳传来，为传经次第之正传，自太阳传
来则为误治之坏证矣。
《伤寒论》原文∶本太阳病，医反下之，因而腹满时痛者，属太阴也，桂枝加芍药汤主之；大实痛者，桂
枝加大黄汤主之。
太阳病误下之后，外感之邪固可乘虚而入太阴，究之，脾土骤为降下所伤，肝木即乘虚而侮脾土，腹中
之满而且痛，实由肝脾之相龃龉也。桂枝原为平肝、和脾（气香能醒脾，辛温之性，又善开脾瘀）之圣药，
而辅以芍药、甘草、姜、枣，又皆为柔肝扶脾之品，是桂枝汤一方，若免去啜粥，即可为治太阴病之正药也。
至于本太阳证，因误下病陷太阴，腹满时痛，而独将方中芍药加倍者，因芍药善治腹痛也。试观仲景用小柴胡
汤，腹痛者去黄芩加芍药，通脉四逆汤腹痛者，去葱加芍药此明征也。若与甘草等分同用，为甘草芍药汤，
原为仲景复阴之方，愚尝用之以治外感杂证、骤然腹痛（须审其腹痛非凉者），莫不随手奏效。惟其所用之分
量，芍药倍于甘草是为适宜，盖二药同用原有化合之妙，此中精微固不易窥测也。且二药如此并用，大有开
通之力，则不惟能治腹痛，且能除腹满也。
惟此方中芍药加倍为六两，甘草仍为二两，似嫌甘草之力薄弱，
服后或难速效，拟将甘草亦加重为三两，应无药性偏重之弊欤。
【桂枝加芍药汤方】桂枝三两，芍药六两，甘草二两炙，生姜三两切，大枣十二枚擘。
上五味，以水七升，煮取三升，去滓，分温三服。
【桂枝加大黄汤方】即前方加大黄二两。
太阴病的证候，并不一定都是由少阳病传变而来，也有偶尔从太阳病传变而来的情况。然而，从少阳病传来，属于疾病按经络次序传变的正常过程；而从太阳病传来，则属于因误治导致的坏证（病情恶化或转变的复杂证候）。
《伤寒论》原文记载：原本是太阳病，医生反而使用了攻下法，导致腹部胀满、间歇性疼痛的，属于太阴病，应当用桂枝加芍药汤主治；如果疼痛剧烈且伴有实邪阻滞（大实痛），则用桂枝加大黄汤主治。
太阳病经过误用攻下法后，外感的风寒邪气固然可以乘体内正气虚弱而侵入太阴脾经，但究其根本，脾土突然受到攻下药物的损伤，肝木就会乘虚克制脾土（中医五行理论中，木克土，此处指肝气横逆犯脾），腹中的胀满和疼痛，实际上是由于肝脾功能失调、相互冲突所致。桂枝本是平抑肝气、调和脾气（气味芳香能醒脾，辛温的性质善于疏通脾部瘀滞）的良药，再辅以芍药、甘草、生姜、大枣，这些也都属于柔养肝气、扶持脾气的药物。因此，桂枝汤这一方剂，如果去掉服药后喝热粥以助药力的步骤，就可以作为治疗太阴病的正药。
至于原本的太阳病证，因为误用攻下法导致病邪陷入太阴，出现腹部胀满、间歇性疼痛，而唯独将方中的芍药剂量加倍，是因为芍药擅长治疗腹痛。试看张仲景在使用小柴胡汤时，若患者有腹痛，就去掉黄芩加入芍药；在使用通脉四逆汤时，若患者有腹痛，就去掉葱白加入芍药，这些都是明确的证据。如果将芍药与甘草等量同用，称为甘草芍药汤，这原本是张仲景用于恢复阴液的方子，我曾用它治疗外感杂病引起的骤然腹痛（必须辨证确认腹痛不是由寒凉引起），没有不随手见效的。只是其中使用的剂量比例，芍药是甘草的两倍才最为适宜，因为这两味药同用确实有化合协同的妙处，其中的精微奥妙本来就不容易窥测。而且这两味药这样配合使用，具有强大的开通散结之力，因此不仅能治疗腹痛，还能消除腹部胀满。
只是在这个方子中，芍药加倍至六两，甘草仍为二两，似乎显得甘草的药力薄弱，服用后或许难以迅速见效，我打算将甘草也加重到三两，应该不会有药性偏重失衡的弊端吧。
【桂枝加芍药汤方】桂枝三两，芍药六两，甘草二两（炙），生姜三两（切），大枣十二枚（掰开）。
以上五味药，用水七升，煎煮取汁三升，去除药渣，分三次温服。
Taiyin disease patterns do not necessarily all arise from transmission from Shaoyang; occasionally, they may also be transmitted from Taiyang. However, transmission from Shaoyang represents the normal sequential progression of disease through the meridians, whereas transmission from Taiyang constitutes a "huai zheng" (bad complication or deteriorated syndrome resulting from mismanagement).
The original text of *Shanghan Lun* states: "Originally a Taiyang disease, if the physician erroneously applies purgation, leading to abdominal fullness and intermittent pain, it belongs to Taiyin; Guizhi Jia Shaoyao Tang (Cinnamon Twig Decoction with Added Peony) is the primary treatment. If there is severe pain with excess accumulation (da shi tong), Guizhi Jia Dahuang Tang (Cinnamon Twig Decoction with Added Rhubarb) is the primary treatment."
After erroneous purgation in a Taiyang disease, external pathogenic factors may indeed invade the Taiyin Spleen due to deficiency. Fundamentally, however, the Spleen Earth is suddenly injured by the downward-purging action, causing Liver Wood to exploit this weakness to overact upon Spleen Earth (Wood insulting Earth). The abdominal fullness and pain are essentially caused by disharmony and conflict between the Liver and Spleen. Guizhi (Cinnamon Twig) is originally a supreme herb for calming the Liver and harmonizing the Spleen (its aromatic fragrance awakens the Spleen, and its acrid-warm nature effectively opens Spleen stasis). When assisted by Shaoyao (Peony Root), Gancao (Licorice Root), Shengjiang (Fresh Ginger), and Dazao (Jujube Fruit)—all of which are substances that soften the Liver and support the Spleen—the Guizhi Tang (Cinnamon Twig Decoction) formula, if the instruction to drink hot porridge after administration is omitted, can serve as the correct medicine for treating Taiyin disease.
Regarding the original Taiyang syndrome, where erroneous purgation causes the pathology to sink into Taiyin, presenting with abdominal fullness and intermittent pain, the reason for doubling the dosage of Shaoyao (Peony Root) in the formula alone is that Shaoyao excels at treating abdominal pain. Observe Zhang Zhongjing’s use of Xiaochaihu Tang (Minor Bupleurum Decoction): when abdominal pain is present, Huangqin (Scutellaria Root) is removed and Shaoyao is added. Similarly, in Tongmai Sini Tang (Pulse-Reviving Four Reversals Decoction), when abdominal pain is present, Congbai (Scallion White) is removed and Shaoyao is added. These are clear evidences. If Shaoyao is used in equal proportion to Gancao, it forms Gancao Shaoyao Tang (Licorice and Peony Decoction), which was originally Zhang Zhongjing’s formula for restoring Yin. I have used it to treat sudden abdominal pain arising from exogenous miscellaneous diseases (provided one verifies that the pain is not cold-type), achieving immediate efficacy in every case. However, the dosage ratio where Shaoyao is double that of Gancao is most appropriate, as the combination of these two herbs possesses subtle synergistic effects, the intricacies of which are difficult to fully fathom. Moreover, using them together in this manner provides significant unblocking power, thereby not only treating abdominal pain but also eliminating abdominal fullness.
In this formula, although Shaoyao is doubled to six liang, Gancao remains at two liang, which seems insufficiently potent; thus, rapid efficacy might be difficult to achieve after administration. I propose increasing the dosage of Gancao to three liang, which should avoid any disadvantage of imbalance in medicinal properties.
[Guizhi Jia Shaoyao Tang Formula] Guizhi (Cinnamon Twig) 3 liang, Shaoyao (Peony Root) 6 liang, Gancao (Licorice Root) 2 liang (roasted), Shengjiang (Fresh Ginger) 3 liang (sliced), Dazao (Jujube Fruit) 12 pieces (split open).
Take the above five ingredients, add seven sheng of water, decoct to obtain three sheng of liquid, remove the dregs, and divide into three warm doses.
[Guizhi Jia Dahuang Tang Formula] This is the aforementioned formula with the addition of Dahuang (Rhubarb Root) 2 liang.