The Herb Cabinet 本草

芦根 lú gēn

Phragmites communis · reed rhizome

Cold Sweet LungStomach

“The common reed of every riverbank, dug for its sweet water-storing root. When fever has drunk the body dry, this is the drawer that pours a glass.” — Lao Xinglin

What the tradition says

The world's most ordinary wetland plant stores sweet juice in its rhizome, and the tradition put it to the most humane of jobs: generating fluids — quenching the thirst of fevers, soothing the irritable dry heat in lung and stomach, easing the nausea of a hot stomach and, in the old lung-abscess formulas, clearing heat with pus^[1]. Fresh, it is practically a beverage; in Yin Qiao San it re-moistens what wind-heat has parched while the flowers fight.

What the research says

Essentially unstudied as a lone medicine — some laboratory antioxidant work on reed polysaccharides — and essentially unquestioned as a safe one: it is closer to sugarcane water than to pharmacology, which is precisely its role.

Where to be careful

Only the obvious: cold and moistening, so unhelpful where the pattern is cold and damp already^[1]. Otherwise, one of the few drawers the tradition let fever patients drink freely.

In the pharmacy

Segmented, hollow, pale-gold rhizomes — fresh and juicy in southern markets (the better grade, says tradition), dried elsewhere; boiled into the pleasant, faintly sweet "reed root water" of convalescent kitchens^[1].

Reviewed 2026-08-26