Witnessed by: TCM · Western
Japanese knotweed (Polygonum cuspidatum), of the Polygonaceae family. Vigorous rhizomatous perennial with hollow, jointed, red-speckled canes to 2–3 m; native range: Eastern Asia — Japan, China, Korea and Taiwan; naturalised and famously invasive across Europe and North America. Globally recognized as hu zhang (虎杖) in Chinese, and hu zhang, Mexican bamboo, tiger cane, giant knotweed in English. The part used is root and rhizome (dried). Woody knotted rhizome, orange-yellow within; bitter and faintly astringent, the cut surface staining yellow from anthraquinones.
In this cross-tradition database, we analyze how this substance operates across world medicine systems — tracking its traditional tastes, temperatures, tissue affinities, post-digestive effects, and planetary correspondences across Ayurveda, Unani, and Western herbalism.
JAPANESE KNOTWEED
IDENTITY
Name
- Common
- Japanese knotweed
- Scientific name
- Polygonum cuspidatum Siebold & Zucc.
- Family
- Polygonaceae
Form
- Part used
- root and rhizome (dried)
PROPERTIES
Nature
Taste
how the plant declares itself on the tongue
- TCM
- bitter
- Western
- bitter · astringent
Temperature
- TCM
- cold
- Western
- cold
Affinity
where in the body it travels
Organs / channels
- TCM
- Liver · Gallbladder · Lung
- Western
- liver · blood · circulation · lungs
PRACTICE
Virtue
Actions
- TCM
- clears heat and drains damp-heat, invigorates the blood and dispels stasis, resolves toxicity, transforms phlegm and stops cough, and unblocks the bowels
- Western
- antioxidant, cardioprotective, anti-inflammatory, antimicrobial and mild anthraquinone laxative; a leading source of resveratrol and emodin
Cautions
Contraindications: pregnancy (a blood-invigorating, uterine-active herb); loose stools from spleen-cold; long high-dose use of the anthraquinone fraction
Toxicity: emodin and related anthraquinones can loosen the bowel and gripe in large doses; the plant is high in oxalates
Interactions
- Western
- anticoagulants: resveratrol adds antiplatelet and mild anticoagulant effect · CYP450-metabolised drugs: resveratrol and emodin modulate CYP3A4/CYP2C isoenzymes, altering drug levels
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