Perfoliate Knotweed gàng bǎn guī · 杠板归

Polygoni Perfoliati Herba (Polygonum perfoliatum L.)

Nature and flavour. Sour, bitter, slightly cold. Lung and Small Intestine systems.

A creeping knotweed with triangular leaves and a stem armed with recurved prickles — the prickles are why it is called 刺犁头 in some local naming. Traditional texts describe it as clearing heat and resolving toxin, draining water and dispersing swelling, and relieving cough. It is used both internally and, more often in the classical sources, pounded fresh for external application on swellings, insect bites and the skin eruptions grouped under damp-heat. These are recorded traditional indications, not established ones.