A "harmonize shaoyang and drain yangming" formula from the Han dynasty, the natural counterpart to Xiao Chaihu Tang, but with rhubarb added to address simultaneous interior heat and constipation.
Cultural reference - how this formula has been discussed in Chinese medical tradition. Not medical advice.
Background & origin
Compiled by Zhang Zhongjing in the "Treatise on Cold Damage" (《伤寒论》) as the formula for the combined shao-yang/yang-ming stage. In Japan, Dai-saikoto (大柴胡湯) is sold by every major kampo manufacturer (Tsumura, Kracie, Kotaro) as the standard OTC for "robust body type with chest-and-flank fullness, bitter taste, and constipation", a classical "thick-set, red-faced, irritable" presentation. In Korea it appears as Daesiho-tang (대시호탕) in the Kyungdong hanbang line.
From the source text
This page is cultural documentation, not medical advice.
From the source text · 卷三·辨太阳病脉证并治中·第 103 条
Classical text
太阳病，过经十余日，反二三下之，后四五日，柴胡证仍在者，先与小柴胡汤。呕不止，心下急，郁郁微烦者，为未解也，与大柴胡汤下之则愈。
Modern Chinese rendering
太阳病已过经十余日，反而多次用下法，后四五日柴胡证仍在的，先用小柴胡汤。若见呕吐不止、心下拘急、郁郁微烦者，为少阳兼阳明里实未解，可与大柴胡汤下之则愈。这是"少阳阳明合病"思路下，少阳证未罢而兼阳明里实已成时，用大柴胡汤"和解少阳、内泻热结"的代表性条文。
Editorial translation
When a taiyang disorder has already passed through the channels for more than ten days and purgation has been wrongly applied two or three times, if after another four or five days the chaihu pattern is still present, give Xiao Chaihu Tang first. If, however, there is unceasing retching, a tight and pressing sensation below the heart, and a slightly oppressive irritability, then the disorder has not been resolved, and Da Chaihu Tang is given to drain it, after which recovery follows. This is the canonical clause for the combined "shaoyang with yangming interior excess" reasoning, used when the shaoyang pattern has not lifted and interior heat and binding in the yangming has already formed, where Da Chaihu Tang simultaneously "harmonizes the shaoyang" and "internally drains the heat binding".
In tradition
In TCM tradition, associated with the combined "shao-yang and yang-ming" pattern, alternating chills and fever, fullness in the chest and flanks, irritability, nausea, and constipation or hard stools, all at the same time. It is the formula of choice when a "shao-yang" presentation is accompanied by clear signs of interior heat and dryness of the bowels. It is also commonly discussed for acute abdominal discomfort in a robust adult with a history of overindulgence.
Formula composition
Monarch1
- Bupleurum root (Chái Hú / 柴胡) - the principal herb
Other ingredients7
- Scutellaria root (Huáng Qín / 黄芩)
- Pinellia rhizome, processed (Bàn Xià / 半夏)
- Ginger (Shēng Jiāng / 生姜)
- Chinese date (Dà Zǎo / 大枣)
- White peony root (Bái Sháo / 白芍)
- Bitter orange (Zhǐ Shí / 枳实)
- Rhubarb root (Dà Huáng / 大黄)
International availability
Taiwan & Hong Kong
- 順天堂OTC大柴胡湯Da Chai Hu Tang
Cautions & context
- Contains rhubarb (Dà Huáng), a stimulant laxative. Loose stools or cramping are possible, especially in sensitive individuals.
- Not appropriate during pregnancy, rhubarb and pinellia are contraindicated.
- Considered inappropriate for thin, weak, or chronically tired patients in TCM framing, the formula is for robust "excess" presentations.
- Severe abdominal pain, especially with fever or vomiting, requires medical evaluation before use, appendicitis and other acute abdominal conditions can mimic this presentation.
Related formulas
Other formulas from this text· "Treatise on Cold Damage"
Other formulas by this contributor· Zhang Zhongjing
Related concerns
Concern · digestion
Digestion
Upper-abdominal heaviness, bloating, sour reflux, loose stools, traveler's stomach, and the aftermath of a meal that was richer, spicier, or larger than usual.
Editorial note
Compiled from "Treatise on Cold Damage" (200).
Last reviewed: July 18, 2026
Three layers of evidence
Classical source
≈ 1800 years · "Treatise on Cold Damage" (200)
Pharmacopoeia indication
"Harmonize the Shaoyang, internally drain heat binding. Used for Shaoyang-Yangming combined disease: alternating chills and fever, chest and hypochondriac fullness and discomfort, incessant vomiting, hard glomus below the heart, fullness and pain below the heart, no bowel movement, or heat-associated diarrhea."
Modern research status
As of 2026-07-18, a PubMed search using the formula name and the Latin / Korean / Japanese transliterations together with "systematic review" and "meta-analysis" did not identify a dedicated systematic review for this formula. Any clinical evidence that does exist is fragmented across small individual trials or covered in broad herbal-medicine umbrella reviews, which do not allow a per-formula evidence assessment; the absence of a dedicated SR is itself the relevant editorial fact here.
References
References reviewed on July 18, 2026 · PubMed search on 2026-07-18
- 01ClassicalZhang Zhongjing, 《伤寒论》 (Shānghán Lùn / Treatise on Cold Damage), Eastern Han dynasty, c. 200 CE, with the base formula appearing in clause 103 of the "taiyang" section, the canonical text for the combined "shaoyang with yangming interior excess" pattern.
- 02TextbookDuan Fuqin (段富津) et al. (eds.), 《方剂学》 (Fāngjìxué / Textbook of Formulas), Shanghai Scientific and Technical Publishers, 1995, the standard modern university-level formula textbook in mainland China, with Da Chaihu Tang analysed as the representative "harmonize shaoyang and drain yangming" formula.
- 03PharmacopoeiaChinese Pharmacopoeia Commission, 《中华人民共和国药典》 2020 年版一部 (Zhōnghuá Rénmín Gònghéguó Yàodiǎn, Pharmacopoeia of the People's Republic of China, 2020 Edition, Vol. I), China Medical Science Press, 2020, the official monograph for Da Chaihu Tang / Da Chaihu Keli dosage forms.