☯ TCM Properties
Dispels Wind, eliminates Dampness, invigorates the Blood and dredges and unblocks the channels and collaterals; Clears Heat, resolves toxicity, stops diarrhea, generates flesh and stops itching
Traditional Chinese Uses
Lao Guan Cao, the aerial parts of Geranium wilfordii and related cranesbills (Herba Erodii seu Geranii), is acrid, bitter and neutral, entering the liver, kidney, spleen and large intestine channels. As a wind-damp-dispelling herb it unblocks the channels and collaterals and invigorates the blood, making it a common remedy for wind-damp painful obstruction (bi syndrome): rheumatic and arthritic joint pain, muscular contracture, numbness of the limbs, and soreness and weakness of the lower back and knees. Its second sphere of action is clearing heat and resolving toxicity to stop diarrhea and dysentery; astringent and antimicrobial, it is used for damp-heat enteritis and dysenteric disorders, and applied topically to generate flesh, stop itching and heal sores. It is often combined with other channel-freeing herbs in wind-cold-damp formulas.
Western Herbalism Properties
Botanical Description
Lao Guan Cao (老鹳草) refers to several cranesbill species in the Geraniaceae family, principally Geranium wilfordii, Geranium carolinianum, and Erodium stephanianum. These are low-growing annual or perennial herbs reaching 20–60 cm tall, with palmately divided or pinnately compound leaves and slender, branched stems often clothed in fine hairs. Solitary or paired five-petaled flowers in pink, lavender, or pale purple appear in summer, followed by the diagnostic long-beaked schizocarpic fruits that resemble a crane's bill and split elastically at maturity to disperse seeds. The dried aerial portions, collected during flowering and fruiting, constitute the medicinal substance Lao Guan Cao Cao recorded in the Chinese Pharmacopoeia.
Active Constituents
Geraniin
Ellagitannin (hydrolyzable tannin)Concentration: Principal tannin, highest-content marker
The characteristic and most abundant tannin of the herb, with broad anti-inflammatory, antioxidant, antiviral, antihypertensive and organ-protective activity; central to the traditional actions of dispelling wind-damp, resolving toxicity and stopping diarrhea.
Corilagin
Ellagitannin (hydrolyzable tannin)Concentration: Major tannin (second most abundant)
A hydrolysis product of geraniin with documented anti-inflammatory, antioxidant and hepatoprotective activity, contributing to the herb's heat-clearing and detoxifying effects.
Ellagic acid
Ellagitannin-derived polyphenolConcentration: Major phenolic
An antioxidant and anti-inflammatory polyphenol formed on tannin hydrolysis; supports the astringent, antidiarrheal and tissue-protective properties.
Gallic acid
Phenolic acidConcentration: Common phenolic acid
Provides antioxidant, antimicrobial and astringent activity typical of tannin-rich Geraniaceae herbs.
Quercetin and hyperoside
Flavonol / flavonol glycosideConcentration: Secondary flavonoids
Flavonoids that add antioxidant, anti-inflammatory and vascular-protective effects, complementing the tannin fraction in relieving joint pain.
Protocatechuic acid
Phenolic acidConcentration: Minor phenolic
A minor antioxidant phenolic acid documented among the herb's active constituents.
⚠ Drug Interactions
Oral iron salts and mineral supplements
The high content of hydrolyzable tannins (geraniin, corilagin) can chelate dietary and supplemental iron and other divalent cations, forming insoluble complexes that may reduce their absorption — a general property of tannin-rich herbs rather than a herb-specific clinical finding.
Clinical note: Theoretical; separate ingestion of tannin-rich decoctions from iron supplements.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 9-15g | Daily | — | — | — |
Preparation Methods
Decoction
Parts: Aerial parts (whole herb)
Decoct 9–15 g of the dried herb to dispel wind-damp, unblock the channels and relieve rheumatic joint pain, numbness and cramps; also used for damp-heat diarrhea and dysentery.
Medicinal wine / topical wash
Parts: Aerial parts (whole herb)
Soaked in wine for internal use against wind-damp pain, or decocted and applied as an external wash for sores and itching, drawing on its heat-clearing, toxicity-resolving and flesh-generating actions.
Historical Texts
Ben Cao Gang Mu Shi Yi (Supplement to the Compendium of Materia Medica), Zhao Xuemin
Qing dynasty (1765)References
- Kong C, Pang X, Su Z, Liu Y. Botany, ethnopharmacology, phytochemistry and pharmacology of Erodii Herba Geranii Herba — A review . Journal of Ethnopharmacology (2023) [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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