Traditionally used for
- Nose & throat
- Cough & breathing
- Bowel health
- Urinary & fluids
- Skin
☯ TCM Properties
Clears Heat and eliminates toxicity; Promotes diuresis and disperses swelling; Invigorates the Blood
Traditional Chinese Uses
Gang Ban Gui is the aerial parts of Persicaria perfoliata (syn. Polygonum perfoliatum), a barbed climbing knotweed. In traditional Chinese medicine it is a cooling, sour-bitter herb that clears Heat and relieves Fire toxicity, promotes urination to reduce swelling, and invigorates the Blood. It is used for damp-heat and toxic-heat patterns: sore, swollen throat and lung-heat cough (including whooping cough), edema with scanty urination, damp-heat diarrhea and dysentery, and bleeding hemorrhoids. Externally the fresh herb is crushed and applied for eczema, weeping sores, boils, and snake or insect bites.
It is typically decocted, with larger amounts of the fresh plant used for topical washes and poultices, and combined with other heat-clearing, toxin-resolving herbs for throat and skin complaints.
Relationships
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Botanical Description
Gang Ban Gui is a regional folk-medicine name without a confirmed botanical identification in standard Chinese Materia Medica references. The name translates roughly as "steel-plank cassia" or similar, and may refer to a Cinnamomum-related bark or a Dalbergia-type wood in particular districts, but no authoritative source associates it with a single binomial. The Chinese Pharmacopoeia, Bensky and Gamble, and Flora of China do not list this name. Without a verified botanical referent, no reliable description of morphology, parts used or therapeutic actions can be given.
Active Constituents
Quercetin
Flavonol aglyconeConcentration: 15.67-50.19 micrograms per gram of the dried herb across 15 Chinese sources, and undetectable in 3 of those 15 samples
The Chinese Pharmacopoeia uses quercetin content as the quality assay marker for this drug, and it is the most abundant of the five marker compounds measured. It scavenges free radicals and inhibits NF-kB signalling, which is the usual mechanistic account offered for the herb's heat-clearing and toxin-resolving use.
Caffeic acid
Hydroxycinnamic acidConcentration: 4.43-28.35 micrograms per gram of the dried herb; detected in all 15 sources sampled
The most consistently present of the marker phenolics, found in every sample tested. Reported antiviral and anti-inflammatory activity is attributed to it alongside quercetin and gallic acid.
Hyperoside (quercetin 3-O-galactoside)
Flavonol glycosideConcentration: 0-18.31 micrograms per gram of the dried herb; absent from the Kunming sample
Hyperoside affects glomerular filtration rate and aquaporin expression, which is the mechanism usually invoked for the diuretic and anti-swelling use of the herb.
Gallic acid
Hydroxybenzoic acidConcentration: 0.49-2.21 micrograms per gram of the dried herb; undetectable in 2 of 15 sources
A minor but widely distributed phenolic acid of the herb, contributing to its radical-scavenging capacity.
Isorhamnetin
Methylated flavonolConcentration: 0-1.43 micrograms per gram of the dried herb, the least abundant of the five markers
A minor flavonol of the herb with the same broad anti-inflammatory and antioxidant profile as quercetin, from which it is derived by 3'-O-methylation.
Tannins
PolyphenolsConcentration: reported as one of the principal constituent classes of the herb alongside flavonoids and alkaloids; not quantified in the sources consulted
Tannins account for the astringent character of the crude drug. They are the constituent class most likely to matter for co-administered oral drugs, since tannins bind metal ions and basic drug molecules in the gut lumen.
⚠ Drug Interactions
Oral iron salts (ferrous sulfate, ferrous fumarate)
Tannins are described as one of the principal constituent classes of Persicaria perfoliata, alongside flavonoids and alkaloids. Polyphenolic tannins chelate non-haem iron in the gut lumen and form poorly absorbed complexes. No study has tested this with Persicaria perfoliata specifically, so this is inferred from the herb's constituent class rather than observed, and is recorded as theoretical for that reason.
Clinical note: If a patient is taking oral iron, separate it from the decoction by two hours. Do not treat this as a documented interaction of the herb; it is a class inference from its tannin content.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 15–30 g | Daily | — | — | 中国药典 2020 monograph 【杠板归】【用法与用量】15～30g。外用适量，煎汤熏洗。 【性味与归经】酸，微寒。归肺、膀胱经。 — Matched to ChP by romanised drug name (pinyin 'Gang Ban Gui' → 杠板归); the romanisation is unique across all 649 ChP monographs, and the match was cross-checked against this record's own TCM temperature. Quoted verbatim. |
Evidence Tier
Moderate evidence · 3 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
1 verified · 2 unverified
Show 3 studies
- Qualitative analysis of chemical constituents and study on the biological activity of Polygonum perfoliatum L.
- Extraction and Purification of Flavonoids and Antiviral and Antioxidant Activities of Polygonum perfoliatum L.
- Polygonum perfoliatum L. ethanol extract ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin inflammation
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Qualitative analysis of chemical constituents and study on the biological activity of Polygonum perfoliatum L.
UPLC-MS/MS profiling of Polygonum perfoliatum (the accepted name of which is Persicaria perfoliata) identified 94 constituents, comprising 32 flavonoids, 5 phenylpropanoids, 6 phenols, 6 alkaloids, 13 fatty acyls, 6 organic acids, 12 amino acids and peptides, and 14 compounds of other classes. The ethanol extract showed concentration-dependent antioxidant capacity, inhibited alpha-glucosidase with an IC50 of 1.643 micrograms/mL, and inhibited MV4-11 and SW480 cell lines with IC50 values of 237.5 and 157.6 micrograms/mL respectively. This is cell and enzyme work only; no patients were involved.
Extraction and Purification of Flavonoids and Antiviral and Antioxidant Activities of Polygonum perfoliatum L.
Total flavonoids were extracted from Persicaria perfoliata (published under the synonym Polygonum perfoliatum) at a yield of 14.98 mg/g and purified on macroporous resin and a resin-polyamide column to 59.02% purity. Seventy-nine flavonoids were identified by UPLC-HRMS. The purified flavonoid fraction showed activity against varicella-zoster virus and antioxidant activity in cell-free and cell-based assays. No clinical endpoint was studied.
Polygonum perfoliatum L. ethanol extract ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin inflammation
An ethanol extract of Persicaria perfoliata (published as Polygonum perfoliatum) was applied topically as a gel for 21 days to mice with 2,4-dinitrochlorobenzene-induced atopic dermatitis-like lesions. Epidermal thickness and dermatitis severity fell, as did TNF-alpha, IL-6, IL-1beta, IL-4, IL-5, IL-13 and IgE. iNOS and COX-2 expression and phosphorylation of p38 MAPK and NF-kB were suppressed, and the raised CD4+/CD8+ ratio was normalised. A skin irritation test showed no toxicity at 10 mg/day. This supports the traditional eczema use at the level of a mouse model only.
References
- Zhang Y; Zhao L; Wang X; Zhang C; Zuo H; Gao D. Impact of Geographical Origin on the Contents of Inorganic Elements and Bioactive Compounds in Polygonum perfoliatum L. . Molecules (2025) [DOI]
- Wu W; Tan S; Meng Q; Lei N; Xue J; Gong Z; Chai H; Mi Y; Hou Y. Ethanol extract of Polygonum perfoliatum L. alleviates inflammation and ferroptosis in ulcerative colitis . Phytomedicine (2025) [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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