Bupleurum: Chai Hu in Traditional Chinese Medicine

Chai hu (柴胡), the root of Bupleurum, has been part of Chinese herbal medicine for more than two thousand years, according to modern reviews of the genus. It is rarely given alone. Its importance comes from the formulas it anchors: xiao chai hu tang, recorded in the Han-dynasty classic on febrile disease; xiao yao san, from a Song-dynasty state formulary; and many relatives. Through Japan's Kampo medicine the same formulas became standardized prescription products, with the root read as saiko.

This page explains, in plain language, what traditional medicine says chai hu does, how those ideas are organized, which plants count as the real herb, and where the tradition and modern research meet or part. The traditional claims are reported as traditional claims. Where modern research tested them, the research is described with its study type.

Table of Contents

  1. A Long Record
  2. How Chinese Medicine Describes Chai Hu
  3. What "the Liver" Means Here
  4. The Main Formulas
  5. Which Plant Is Chai Hu?
  6. Preparation in Practice
  7. From China to Japan: Kampo
  8. Where Tradition and Research Meet
  9. Safety in the Traditional Frame
  10. Terms Used on This Page
  11. Key Research Papers
  12. Connections

A Long Record

A 2023 review of the genus states there is "a long history of using the genus Bupleurum in traditional herbal medicine that dated back to over 2000 years ago," and a 2018 review says Radix Bupleuri "has been widely used in Chinese Traditional Medicine for over 2000 years." The 2011 Heidelberg review calls it "one of the most successful and widely used herbal drugs in Asia."

The best-known early formula, xiao chai hu tang, is recorded in the Shanghan lun (often translated Treatise on Cold Damage), according to a 2010 systematic review; a 2006 case report describes it as first prepared in the Han dynasty (206 BC–AD 220) (J Chin Med Assoc 2006). Xiao yao san was first recorded in the Song dynasty's Taiping Huimin Heji Jufang (Front Pharmacol 2022).

Use spread well beyond China. The 2023 review lists China, Japan, India, Central Asia, North Africa and some European countries as places where bupleurum species are traditional medicines, and the 2024 depression review names China, Japan and Korea as places where chai hu has been used as a mood medicine for centuries.

How Chinese Medicine Describes Chai Hu

Traditional Chinese medicine classifies each herb by taste, "temperature" and the organ systems (meridians) it is said to enter. A 2026 review of the closely related Bupleurum marginatum describes it in those terms as pungent and bitter, slightly cold, and associated with the liver, gallbladder and lung meridians. These are categories of a traditional system, not measurements: "cold" means the herb is used for conditions described as "heat," not that it lowers body temperature in a measurable way.

The same review lists the herb's traditional functions:

The 2023 genus review records a matching list of traditional indications: fever, pain, liver disease, inflammation, chest and lower-back pain, irregular menstruation and rectal prolapse.

What "the Liver" Means Here

The "liver" of Chinese medicine is a traditional functional system that includes the regulation of emotion, and is not the same thing as the organ of anatomy. A 2022 review describes xiao yao san as the formula most commonly prescribed for anxiety and depression attributed to "liver Qi stagnation, blood deficiency, and spleen deficiency" (Front Pharmacol 2022).

That is why the same herb appears in modern research on two quite different subjects: hepatitis and fatty liver on one side, depression on the other. The 2024 review describes chai hu's traditional use both "for liver conditions such as hepatitis, liver inflammation, liver fibrosis, and liver cancer" and as a jie yu, depression-relieving, medicine. The Saikosaponins and the Liver and Xiao Yao San and Mood Research pages report what modern studies found in each area.

The Main Formulas

Combination is central to Chinese herbal practice, and it is also why trials of these formulas cannot attribute an effect, good or bad, to bupleurum alone.

Which Plant Is Chai Hu?

A 2025 review states that the medicinal material is "the dried roots of either ... Bupleurum chinense DC or Bupleurum scorzonerifolium Willd." A 2021 review describes Bupleuri Radix in the same way. These are the official sources.

The genus is much larger. The 2023 review counts about 248 accepted species and notes that 25 species and 8 varieties, with 3 variants, have been reported as effective in traditional use. Local species are used in some regions. Bupleurum marginatum, called "bamboo-leaf bupleurum" or Dian chai hu, is used by ethnic minorities in south-west China, sometimes as the whole plant rather than the root. Its 2026 review describes "market confusion," "high similarity to Bupleurum chinense," the "absence of exclusive markers" to tell them apart, and the lack of an independent quality standard.

Species matter for both effect and safety. The 2011 review stressed "large chemical and biological variations between different species and varieties," and the 2023 review warns that "improper usage of Bupleurum may induce cytotoxic effects," naming polyacetylenes as possibly the main poisonous compounds. A 2014 review of herbal liver injury noted that misidentification of plants is one of the problems complicating case reports.

Preparation in Practice

Traditionally the dried, sliced root is simmered in water with the other herbs of a formula to make a decoction (tang), or ground with them into a powder (san) or made into pills (wan). Modern practice in China and Japan relies heavily on granule extracts and standardized tablets of the classical formulas; a 2018 review notes bupleurum is marketed in China in chai hu shu gan tablets and xiao yao wan tablets. In research, scientists also use purified individual saikosaponins, which no traditional preparation contains in isolation.

Quality control focuses on saikosaponin content. The 2026 B. marginatum review describes current quality measures as total saikosaponins, total flavonoids, and saikosaponins a and d specifically, measured by chromatographic "fingerprints." A 2025 review notes that clinical data on optimal dose, route and safety remain insufficient.

From China to Japan: Kampo

Kampo is Japan's adaptation of Chinese formula medicine, in which the classical formulas are prescribed as standardized preparations. A 2000 review describes shosaikoto as "used clinically to treat patients with chronic hepatitis or cirrhosis in Japan."

That scale of use is why Japan produced the most detailed safety record for a bupleurum formula. A 2017 review of 73 cases of pneumonitis from Japanese herbal medicines found sho-saiko-to most often implicated, and Japan's medicines regulator carried label wording against combining it with interferon. A 2007 Japanese-language study concluded that the lymphocyte stimulation test for shosaikoto gives many false positives. The Sho-Saiko-To and Interstitial Pneumonia page tells that story in full.

Where Tradition and Research Meet

Traditional use tells researchers where to look. It does not, on its own, show that a herb works or that it is safe; the bupleurum record shows both a long tradition of use and specific harms that were recognized only through modern reporting systems.

Safety in the Traditional Frame

Modern reviews add measured concerns to the traditional picture: a 2018 review reports overdose-induced acute and accumulation-related chronic liver toxicity; a 2021 review lists liver toxicity, nerve toxicity, haemolysis and heart toxicity among saikosaponin d's effects in research, and possible effects on drug-metabolizing enzymes; and a 2015 compilation counts xiao chai hu tang among herbal mixtures with established causality in liver-injury cases. A 2014 review of herbal Chinese medicine liver injury concludes that such products "may rarely be associated with hepatotoxicity in some susceptible individuals."

The research raises the most concern for older adults, people with liver disease, people on interferon or other immune-modifying treatment, and people taking prescription medicines. Questions about any formula are for a clinician who knows a person's full medication list.

Terms Used on This Page

Key Research Papers

  1. Ashour ML, Wink M. Genus Bupleurum: a review of its phytochemistry, pharmacology and modes of action. The Journal of pharmacy and pharmacology. 2011;63(3):305-21. PubMed PMID: 21749378
  2. Teng L, Guo X, Ma Y, et al. A comprehensive review on traditional and modern research of the genus Bupleurum (Bupleurum L., Apiaceae) in recent 10 years. Journal of ethnopharmacology. 2023;306:116129. PubMed PMID: 36638855
  3. Yang X, Yu Z, Yang M, et al. Bupleurum marginatum Wall.: A comprehensive review of the traditional uses, phytochemistry, pharmacology, and quality control. Journal of ethnopharmacology. 2026;365:121575. PubMed PMID: 41881320
  4. Sun P, Li Y, Wei S, et al. Pharmacological Effects and Chemical Constituents of Bupleurum. Mini reviews in medicinal chemistry. 2019;19(1):34-55. PubMed PMID: 29956627
  5. Tian Y, Guo J, Jiang X, et al. Exploring the Therapeutic Potential of Bupleurum in Medical Treatment: A Comprehensive Overview. Pharmaceuticals (Basel, Switzerland). 2025;18(9). PubMed PMID: 41011202
  6. Li X, Li X, Huang N, et al. A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins. Phytomedicine : international journal of phytotherapy and phytopharmacology. 2018;50:73-87. PubMed PMID: 30466994
  7. Ran S, Peng R, Guo Q, et al. Bupleurum in Treatment of Depression Disorder: A Comprehensive Review. Pharmaceuticals (Basel, Switzerland). 2024;17(4). PubMed PMID: 38675471
  8. Qin XK, Li P, Han M, et al. [Xiaochaihu Tang for treatment of chronic hepatitis B: a systematic review of randomized trials]. Zhong xi yi jie he xue bao = Journal of Chinese integrative medicine. 2010;8(4):312-20. PubMed PMID: 20388470
  9. Qi FH, Wang ZX, Cai PP, et al. Traditional Chinese medicine and related active compounds: a review of their role on hepatitis B virus infection. Drug discoveries & therapeutics. 2013;7(6):212-24. PubMed PMID: 24423652
  10. Zhou P, Shi W, He XY, et al. Saikosaponin D: review on the antitumour effects, toxicity and pharmacokinetics. Pharmaceutical biology. 2021;59(1):1480-1489. PubMed PMID: 34714209
  11. Teschke R. Traditional Chinese Medicine Induced Liver Injury. Journal of clinical and translational hepatology. 2014;2(2):80-94. PubMed PMID: 26357619
  12. Teschke R, Zhang L, Long H, et al. Traditional Chinese Medicine and herbal hepatotoxicity: a tabular compilation of reported cases. Annals of hepatology. 2015;14(1):7-19. PubMed PMID: 25536637
  13. Inoue M. Shosaikoto as a potential antiatherosclerotic agent. Drug news & perspectives. 2000;13(7):407-12. PubMed PMID: 12937613
  14. Enomoto Y Md, Nakamura Y Md PhD, Enomoto N Md PhD, et al. Japanese herbal medicine-induced pneumonitis: A review of 73 patients. Respiratory investigation. 2017;55(2):138-144. PubMed PMID: 28274529
  15. Nakayama M, Bando M, Hosono T, et al. [Evaluation of the drug lymphocyte stimulation test (DLST) with shosaikoto]. Arerugi = [Allergy]. 2007;56(11):1384-9. PubMed PMID: 18059152
  16. Yang L, Shergis JL, Di YM, et al. Managing Depression with Bupleurum chinense Herbal Formula: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Journal of alternative and complementary medicine (New York, N.Y.). 2020;26(1):8-24. PubMed PMID: 31328996

PubMed Topic Searches

  1. PubMed: Radix Bupleuri in traditional Chinese medicine
  2. PubMed: Bupleurum chinense and B. scorzonerifolium
  3. PubMed: Kampo saiko formulas
  4. PubMed: Bupleurum quality control and species

Connections