Knotgrass (bian xu)

Polygonum aviculare

Traditionally attributed effects: drains damp heat in cystitis, stops itching and was used against worms.

Safety notes

Caution with qi deficiency. Traditional use is no proof of effectiveness; if you are pregnant, breastfeeding, taking medication or have a medical condition, consult a doctor or pharmacist.

Preparation

Aerial parts. Usually as a decoction, together with other herbs.

Use in traditions

Described in the classical Chinese materia medica, in the group 'herbs that drain dampness'. Knotgrass (bian xu) drains fluid in cystitis and urinary stones and is an ingredient of Ba Zheng San. In Europe it was used as 'knotweed' for diarrhoea and bleeding.

Applications

Use by tradition

How different herbal traditions describe this herb. Amounts are traditional guidelines checked for obvious errors; they are not medical advice. For poisonous plants no dosage is given on purpose.

Chinese materia medica

Nature and taste: sweet, bitter, cool
Meridians: bladder

Attributed effects

For painful urination, cystitis and jaundice from damp heat, itchy skin with dampness and against intestinal worms and trichomonas.

Preparation and amount

Traditional dosage: 9–15 g a day, usually in a decoction. One of the most common roadside plants in the world.

Ways to prepare herbs: Decoction
Formulas: Ba zheng san

Sources

All herbs from Asia →