All-Grass Of Common Knotgrass

Chinese
萹蓄
Pinyin
Bian Xu
Latin
Herba Polygoni Avicularis

TCM Properties

Taste
bitter
Temperature
slightly cold
Channels
Urinary Bladder

Traditional Use

Primary Actions

  • Clears heat and promotes urination — used for urinary tract infections, dysuria, urinary stones, and damp-heat stranguria (Lin syndrome) from heat accumulation in the Urinary Bladder
  • Kills intestinal parasites — used for roundworms, hookworms, pinworms, and intestinal parasitic infestations

Secondary Actions

  • Clears damp-heat from skin — used topically for vulvar itching and moist eczema from damp-heat in the skin
  • Clears damp-heat jaundice — used for jaundice with damp-heat accumulation in the Liver-Gallbladder

Classic Formulas

  • Ba Zheng San (八正散) — with Qu Mai, Mu Tong, Che Qian Zi, Hua Shi, Da Huang, Shan Zhi Zi, Gan Cao Shao, and Deng Xin Cao; for damp-heat stranguria with urinary difficulty, pain, and hematuria

Modern Research

Active Compounds

  • Avicularin (quercetin-3-O-arabinoside) — primary flavonoid glycoside; anti-inflammatory, diuretic, and antibacterial
  • Myricitrin and juglanin — flavonoid glycosides with antioxidant properties
  • Quercetin and kaempferol — flavonols; anti-inflammatory and antioxidant secondary metabolites
  • Caffeic acid and chlorogenic acid — phenolic acids with antimicrobial and antioxidant activity
  • Hyperoside (quercetin-3-O-galactoside) — flavonol glycoside; anti-inflammatory
  • Oxalic acid — dicarboxylic acid contributing to astringent action; caution in calcium oxalate nephrolithiasis

Studied Effects

  • Pharmacopoeial quality assessment — UHPLC-CAD and UHPLC-ESI-MS methods validated for quantification of flavonoid glucuronides as primary quality markers; total flavonoid content 0.70–2.20% across European plant material samples (PMID 26047342)
  • Anti-lipase activity — flavonol-3-O-glycosides (avicularin, myricitrin, juglanin) inhibit porcine pancreatic lipase in physiologically relevant IC50 range; suggests applications for metabolic and anti-obesity activity (PMID 31792306)

PubMed References

Safety & Interactions

Contraindications

  • Pregnancy — bitter-cold herb with diuretic and potential uterine-stimulant action; traditional contraindication throughout pregnancy
  • Spleen-Kidney deficiency without damp-heat — cold draining nature depletes Kidney and Middle Jiao Yang with prolonged use

Cautions

  • Oxalic acid content — avoid prolonged high-dose use in patients with history of calcium oxalate nephrolithiasis; may promote further stone formation
  • Diuretic effect may reduce renal clearance time for lithium and other renally excreted drugs — use with caution in patients on these medications
  • MSK page not found — drug interaction data not available from Memorial Sloan Kettering integrative medicine database

Conditions