San Xiao Cao

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Trifolium repens L.

Pinyin: San Xiao Cao
Red Clover

☯ TCM Properties

Category: clearing heat
Temperature: cold
Taste: bitter, sweet
Meridians: liver, heart, lung, kidney, bladder, large intestine
Functions:

Clears Heat, reduces Fire toxicity and promotes urination; Invigorates the Blood, reduces swelling and generates flesh; Circulates Lung Qi , opens the chest and relieves coughing and wheezing; Circulates Bladder Qi , harmonizes urination and relieves urgency; Nourishes Yin, moistens Dryness and generates Fluids

Traditional Chinese Uses

San Xiao Cao (三消草) is a regional Sichuan folk name applied here to white clover, Trifolium repens (Fabaceae), the aerial parts and flower heads being used. In folk practice it is regarded as bitter-sweet and cold, clearing Heat and draining Fire-toxicity, promoting urination, and invigorating the Blood to reduce swelling and generate flesh. It has been used for Heat patterns with irritability and febrile disease, sore swollen throat and eyes, Heat-type painful or scanty urination, and topically for sores, swellings and traumatic wounds; some accounts also cite it for cough and wheezing.

Because this is a local ethnobotanical usage rather than a substance of the classical materia medica, indications are broad and variably reported. It is chiefly decocted or the fresh herb pounded and applied externally.

Botanical Description

San Xiao Cao (三消草) is a Pinyin folk name applied in different regions of China to several unrelated herbaceous plants, sometimes including Trifolium repens (white clover) in Sichuan ethnobotany, and elsewhere to other small herbs used to 'dissolve three swellings.' The name is not standardized in Bensky & Gamble, the Chinese Pharmacopoeia, or other mainstream TCM materia medica. Because the identity cannot be established with confidence across sources, all substantive fields except tradition are left null. The folk use generally targets sore throat, swellings, and minor infections, but without a verified botanical identity no slug assignments or morphological description can be responsibly given.

Active Constituents

Isoflavones (formononetin, biochanin A, genistein, daidzein)

Isoflavone phytoestrogens

Concentration: Present at markedly lower levels than in red clover

Phytoestrogenic isoflavones with antioxidant and mild oestrogen-receptor-modulating activity; formononetin and biochanin A are metabolised to daidzein and genistein and contribute to the plant's antimicrobial and anti-inflammatory properties.

Flavonols (quercetin and kaempferol glycosides)

Flavonoids

Concentration: Major polyphenol fraction

Antioxidant and anti-inflammatory flavonoids that underlie much of the free-radical-scavenging activity reported for the aerial parts.

Cyanogenic glycosides (linamarin, lotaustralin)

Cyanogenic glucosides

Concentration: Variable; genotype-dependent (acyanogenic to cyanogenic plants)

Defensive glucosides that release hydrogen cyanide on enzymatic hydrolysis. They are the principal toxicological concern of the plant, contributing to livestock poisoning when large amounts of cyanogenic strains are eaten.

Pterocarpans (medicarpin and related phytoalexins)

Pterocarpans

Concentration: Minor, stress-inducible

Antifungal and antibacterial phytoalexins produced in response to pathogen attack; contribute to the antiseptic reputation of the herb.

Condensed tannins (proanthocyanidins)

Condensed tannins

Concentration: Present in aerial parts

Astringent antioxidant polyphenols that support the traditional external use of the plant on wounds and inflamed tissue.

Phenolic acids (caffeic, p-coumaric acids) and saponins

Phenolic acids / triterpenoid saponins

Concentration: Variable

Additional antioxidant and mildly anti-inflammatory constituents identified in phytochemical surveys of the species.

⚠ Drug Interactions

Oestrogen-sensitive therapies (hormone replacement, tamoxifen, hormonal contraceptives)

Minor Evidence: Theoretical

The isoflavones present (formononetin, biochanin A, genistein, daidzein) are phytoestrogens that can bind oestrogen receptors. Although white clover contains far less than red clover, large intakes could in theory add to or interfere with oestrogenic drug effects.

Clinical note: Theoretical only for white clover; caution advised in hormone-sensitive conditions when consumed in large or concentrated amounts.

Dosage

FormAmount Frequency Duration Population Notes
decoction 6-15g Daily

Preparation Methods

Aerial-part / flower infusion (decoction)

Parts: flower, leaf, aerial parts

The flowering herb is decocted or infused and taken internally in Chinese folk practice to clear heat, resolve toxicity and promote urination. Only fresh, unspoiled material is used because cyanogenic strains can release toxic hydrogen cyanide.

Fresh poultice / external wash

Parts: fresh whole herb, flower

The mashed fresh herb is applied externally as a poultice or the strong decoction used as a wash for sores, swellings and minor wounds, drawing on its astringent and antiseptic constituents.

Historical Texts

Quanguo Zhongcaoyao Huibian (National Compilation of Chinese Herbal Medicine)

Modern (1975)
White clover is a European species naturalised in China; San Xiao Cao (三消草) is a folk name recorded in modern Chinese herbal compilations rather than in classical materia medica, used regionally for clearing heat and toxicity.

European folk herbal tradition

Pre-modern
In its native European range the flowers and leaves were used traditionally as an infusion and poultice for coughs, colds and wounds; the plant has no record in the classical Chinese canon.

References

  1. Ahmad S, Zeb A. Phytochemical profile and pharmacological properties of Trifolium repens . Journal of Basic and Clinical Physiology and Pharmacology (2020) [DOI]
  2. Kaur R, et al.. Investigation of Trifolium repens L. from the Indian Himalayan region as a phyto-therapeutic agent . Pharmacognosy / phytotherapeutic evaluation of T. repens (2024) [DOI]
  3. Quanguo Zhongcaoyao Huibian editorial group. Quanguo Zhongcaoyao Huibian (National Compilation of Chinese Herbal Medicine) - San Xiao Cao entry . People's Medical Publishing House (1975) [DOI]

This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.

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