Rhizoma Phragmitis
The cooling rhizome of the common reed — a gentle yet effective herb for clearing Lung and Stomach heat, quenching thirst and soothing fever.
What Is Rhizoma Phragmitis?
Rhizoma Phragmitis (芦根, Lú Gēn) is the fresh or dried rhizome of Phragmites communis (common reed), a tall aquatic grass found across wetlands, riverbanks and marshes throughout China and the world. In TCM it is classified as sweet and cold, acting on the Lung and Stomach channels. Its cooling, moistening and mildly diuretic character makes it a gentle but effective herb for addressing heat in the upper and middle Jiao.
Lú Gēn's primary actions centre on clearing heat and generating fluids — making it particularly suited for conditions presenting with thirst, dry mouth, fever, irritability and nausea. It is classically used for early-stage febrile illness, Lung heat with cough or purulent sputum (Lung abscess), and Stomach heat presenting with nausea, vomiting and thirst. Because it is cooling without being harshly draining and moistening without causing stagnation, it is considered a gentle, food-safe herb. Fresh Lu Gen (鲜芦根) is generally considered superior in its fluid-generating and heat-clearing potency.
History & Origin
Lú Gēn has been used in Chinese medicine since antiquity, valued as an accessible and gentle cooling herb available from wetland environments across China. Its inclusion in classical febrile disease formulas reflects its longstanding clinical utility.
Traditional Uses
Febrile Illness & Fever
A classical herb for early-stage exogenous heat conditions, Lu Gen clears heat from the Lung and Stomach, reduces fever and quenches the intense thirst that accompanies febrile illness.
Thirst & Dry Mouth
Its fluid-generating (sheng jin) action makes it one of the best herbs for heat-induced thirst, dry mouth and irritability due to fluid damage.
Lung Heat & Cough
Used for productive cough with yellow sputum and Lung abscess (fei yong) — Wei Jing Tang pairs it with Yi Yi Ren, Dong Gua Ren and Tao Ren for this purpose.
Nausea & Vomiting
Clears Stomach heat that rises to cause nausea, belching and vomiting, often combined with Zhu Ru (bamboo shavings) for synergistic anti-emetic action.
Urinary Difficulty & Dark Urine
Mild diuretic properties assist in clearing heat through the urine, addressing conditions of scanty dark urine and urinary discomfort from heat.
Summer Heat & Prevention
Frequently included in cooling summer herbal teas and drinks in Cantonese and TCM dietary therapy to prevent summer heat conditions and support fluid balance.
Health Benefits
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Clears Heat & Reduces FeverCools Lung and Stomach heat to address febrile conditions, high temperature and the thirst and irritability that accompany them.
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Generates FluidsMoistens and replenishes body fluids damaged by heat, relieving dry mouth, thirst and dryness of the throat.
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Soothes Lung HeatAddresses Lung heat patterns including productive cough with yellow sputum and early-stage Lung abscess.
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Anti-emeticClears Stomach heat to calm upward-rebelling Stomach Qi, reducing nausea and vomiting from heat patterns.
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Gentle & Food-SafeClassified as a food-grade herb, Lu Gen is mild enough for regular dietary use in teas and soups without adverse effects.
The information on this page is for educational and informational purposes only and is not intended as medical advice. Please consult a qualified healthcare practitioner before using any herbal products.
