How does Bupleurum falcatum work in the body?

Bupleurum falcatum contains saikosaponins (A, C, and D) that exert hepatoprotective and anti-inflammatory effects. These compounds modulate immune cell activity, reduce pro-inflammatory cytokine production, and protect liver cells from oxidative damage. The herb also demonstrates antipyretic properties, explaining its traditional use for alternating fever and chills patterns in TCM and Kampo medicine. Evidence level: C.

Does Bupleurum falcatum interact with any medications?

Bupleurum falcatum may interact with immunosuppressant medications due to its immune-modulating properties. It may also affect drugs metabolized by the liver, potentially altering their clearance. Patients taking hepatotoxic medications should exercise caution. Limited clinical interaction data exists (Evidence level: C), so consult a qualified healthcare practitioner before combining with prescription medications.

What is the recommended dosage for Bupleurum falcatum?

The typical adult dosage for Bupleurum falcatum is 3-9 grams of dried root daily, or 500mg of standardized extract taken twice daily. In traditional Kampo and TCM practice, it is often combined with other herbs in formulations rather than used alone. Long-term use should be supervised by a qualified practitioner. Evidence level: C/Traditional.

Is Bupleurum falcatum safe during pregnancy?

Bupleurum falcatum is contraindicated during pregnancy and should be avoided. Traditional sources and safety assessments classify it as unsafe for pregnant women, though specific teratogenic data remains limited. Women who are pregnant, breastfeeding, or attempting to conceive should not use this herb without medical supervision. Evidence level: C/Traditional.

What are the side effects of Bupleurum falcatum?

Bupleurum falcatum may cause gastrointestinal effects including nausea or digestive discomfort in some individuals. In rare cases, particularly within Kampo formulations, interstitial pneumonia has been reported. Long-term use requires caution due to limited safety data. Patients should discontinue use if respiratory symptoms develop and seek immediate medical attention. Evidence level: C.

Thorowax (Bupleurum falcatum)

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 30 PubMed articles · model: gemma4:31b

Summary

Thorowax (Bupleurum falcatum) is an East Asian medicinal herb used traditionally to treat infections, fever, and chronic liver diseases [PMID:26231448].

Background

Bupleurum falcatum L., also known as Chinese Thorowax or Hare's Ear Root, is a member of the Apiaceae family [PMID:27187480, PMID:36553505]. It is cultivated and used extensively in China, Japan, and Korea [PMID:31872731].

Traditional uses

Traditionally used in Asia as a liver tonic [PMID:27187480], for the treatment of cold and liver protection [PMID:31872731], and to treat infections, fever, and chronic liver diseases [PMID:26231448]. In Iranian folkloric medicine, it has been used as a selective analgesic remedy [PMID:33689798].

Active compounds

The main bioactive ingredients are saikosaponins (SSs), specifically saikosaponins a, c, and d [PMID:18262740, PMID:36553505]. Other components include Bupleuri Radix Polysaccharides (BRP) [PMID:36965565] and volatile oils [PMID:36382416].

Mechanism of action

Saikosaponins may inhibit neuroinflammation by inhibiting NF-κB [PMID:26231448]. Saikosaponin B2 suppresses inflammatory responses via IKK/IκBα/NF-κB signaling inactivation [PMID:30251218]. Saikosaponin A may alleviate mastitis by inhibiting ferroptosis via the SIRT1/Nrf2 pathway [PMID:37644785] and attenuate bone loss by inducing ferroptosis in osteoclasts [PMID:39114369]. Saikosaponin D inhibits the fusion of autophagosomes and lysosomes [PMID:3082035 la].

Clinical evidence

Evidence APost-stroke Depression (PSD)

Adjuvant therapy with medicinal plants for Liver-Qi regulation, including Chai-hu (Chinese Thorowax Root), showed significantly higher effectiveness [PMID:27762458].

Evidence CNeurological Disorders (Dementia, Alzheimer's)

Yokukansan (a formula containing B. falcatum) is used to treat insomnia, irritability, and neurological disorders [PMID:20812276].

Evidence DChronic Inflammatory Pain

Saikosaponin A (2 mg/kg, i.p. in rats) produced analgesic effects comparable to acetyl salicylic acid [PMID:36121752].

Evidence DNephrotoxic Serum Nephritis

B. falcatum and saikosaponin d had a significant, though lesser, effect in preventing the development of nephritis in mice [PMID:18262740].

Evidence DAlcohol and Chocolate Self-Administration

B. falcatum extracts reduced alcohol and chocolate self-administration in rats in a dose-related manner [PMID:34652253].

Safety & adverse effects

Yokukansan, which contains B. falcatum, has been reported to have no adverse effects [PMID:20812276].

Evidence summary

The evidence consists primarily of preclinical animal models (D) and a systematic review of adjuvant therapy for post-stroke depression (A). Most pharmacological data are based on isolated saikosaponins rather than whole-herb clinical trials.

PubMed sources

1.PMID: 37265760 (2023) — Analysis of codon usage patterns in Bupleurum falcatum chloroplast genome. · Chinese herbal medicines
2.PMID: 31558860 (2019) — Regulatory effect of a Chinese herbal medicine formula on non-alcoholic fatty liver disease. · World journal of gastroenterology
3.PMID: 36553505 (2022) — Transcriptome Level Reveals the Triterpenoid Saponin Biosynthesis Pathway of Bupleurum falcatum L. · Genes
4.PMID: 18262740 (2008) — Effects of Bupleurum scorzoneraefolium, Bupleurum falcatum, and saponins on nephrotoxic serum nephritis in mice. · Journal of ethnopharmacology
5.PMID: 33457868 (2020) — The complete mitochondrial genome sequences of Bupleurum falcatum (Apiales: Apiaceae).

Thorowax

Sources & Citations