Herb

Lu Gen

Common reed rhizome | 芦根

Also known as:

Phragmites Rhizome

Lu Gen

Product appearance may vary from images shown

Properties

Heat-clearing herbs · Cold

Traditionally supports*

Fever Relief Respiratory Health Digestive Health Urinary Health

Parts Used

Rhizome (根茎 gēn jīng)

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Select Product Type

Select Supplier

Select Size

Quantity

$25.00 ($0.25/g)
For shipments to: United States Change
Standard Shipping (3-5 business days): $4.99
Express Shipping (1-2 business days): $9.99
Free shipping on orders over $75

About This Herb

Traditional Chinese Medicine background and properties

Herb Description

Reed rhizome is a gentle cooling herb commonly used in Chinese medicine to clear Heat from the Lungs and Stomach. It helps relieve fever-related thirst and dry mouth, calms nausea and vomiting, and supports healthy urination. Because it moistens without being heavy, it is especially valued during feverish illnesses where the body's fluids have been depleted.

Herb Category

Heat-clearing herbs Herbs that clear Heat and drain Fire (清热泻火药)

Main Actions

  • Clears Heat and Drains Fire
  • Generates Fluids and Relieves Thirst
  • Eliminates Irritability
  • Stops Vomiting
  • Promotes Urination
  • Expels Phlegm and Discharges Pus
  • Vents Rashes

How These Actions Work

'Clears Heat and drains Fire' refers to Lu Gen's ability to cool internal Heat, especially in the Lung and Stomach. Because it is sweet and cold, it gently clears excess Heat from these organs without being overly harsh. This makes it useful for fevers, restlessness, and thirst caused by Heat in the body's middle and upper regions.

'Generates fluids and relieves thirst' means Lu Gen helps the body produce and preserve its natural moisture. Its sweet taste nourishes fluids while its cold nature clears the Heat that was drying them up. This is why it is widely used in warm-febrile illnesses (Wen Bing) where high fever has depleted body fluids, causing intense thirst and dry mouth. A key advantage of Lu Gen is that it moistens without being heavy or sticky, so it replenishes fluids without trapping pathogenic Heat inside the body.

'Stops vomiting' means Lu Gen can settle the Stomach when Heat causes it to rebel upward. Stomach Heat disrupts the normal downward movement of digestion, leading to nausea, vomiting, or hiccups. Lu Gen clears that Heat and restores the Stomach's natural descending function. It is often paired with Zhu Ru (Bamboo Shavings) for this purpose.

'Promotes urination' means Lu Gen gently encourages fluid movement downward and out through the urinary system. This is helpful when Heat concentrates in the Bladder, causing dark, scanty, or painful urination. It is often combined with Bai Mao Gen (Imperata root) or Che Qian Zi (Plantain seed) for urinary Heat conditions.

'Clears Lung Heat and expels phlegm to discharge pus' describes Lu Gen's particular affinity for the Lungs. When Heat lodges in the Lungs, it can cause cough with thick yellow phlegm, or in severe cases, a lung abscess (Fei Yong) with foul-smelling pus. Lu Gen clears this Heat, thins the phlegm, and helps the body expel infected material. This is the basis for its prominent role in Wei Jing Tang (Reed Decoction).

'Encourages the expression of rashes' means that during febrile illnesses where a rash should appear but is incompletely expressed, Lu Gen can help bring it to the surface. In TCM, an incomplete rash during measles or other eruptive fevers suggests the pathogen is trapped inside. Lu Gen's light, ascending nature helps vent the Heat outward through the skin.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony that reveal what's out of balance in the body. Lu Gen is traditionally associated with these specific patterns.

The following describes this herb's classification within Traditional Chinese Medicine theory and is provided for educational purposes only.

Why Lu Gen addresses this pattern

Lu Gen enters the Lung channel and is sweet and cold, making it well suited to clear Heat that has lodged in the Lungs. Its cold nature directly opposes Lung Heat, while its sweet, fluid-rich quality moistens the Lungs and helps thin thick, sticky phlegm. In cases of Lung Heat progressing to lung abscess (Fei Yong), Lu Gen clears the Heat, promotes the discharge of pus, and nourishes Lung Yin that has been damaged by the Heat. This is why it serves as the King herb in Wei Jing Tang.

A practitioner would look for one or more of these signs

Hypochondrial Pain That Is Worse On Coughing And Breathing

Cough with thick yellow phlegm

Fever

Fever with restlessness

Dry Mouth

Dry mouth and thirst

Chest Pain

Chest pain with foul-smelling sputum in lung abscess

TCM Properties

Temperature

Cold

Taste

Sweet (甘 gān)

Channels Entered
Lungs Stomach
Parts Used

Rhizome (根茎 gēn jīng)

This is partial information on the herb's TCM properties. More detailed information is available on the herb's dedicated page

Product Details

Manufacturing, supplier, and product specifications

Product Type

Granules

Quantity Description

Loading quantity information...

Concentration Ratio

Loading concentration information...

Fabrication Method

Loading fabrication information...

Supplier Certifications

Loading certifications information...

Botanical & Sourcing

Quality Indicators

Good quality Lu Gen (both fresh and dried) should have thick, uniform cylindrical segments with a yellowish-white colour and a natural glossy sheen on the surface. The outer bark should be slightly loose and peelable. Nodes should be clearly visible as ring-shaped bands. The cross-section should be hollow, with a wall thickness of about 1 to 2 mm and small pores arranged in a ring pattern. The herb should feel light in weight but tough and not easily broken. It should have a faint, clean smell and a distinctly sweet taste. Avoid pieces that are thin, dark-coloured, overly fibrous, or have excessive attached rootlets. For dried Lu Gen, the segments become somewhat flattened, with longitudinal wrinkles between nodes. Fresh Lu Gen is clinically preferred and should appear moist, plump, and juicy.

Primary Growing Regions

Lu Gen is produced throughout most provinces of China, as the common reed (Phragmites communis) grows widely in wetlands, rivers, lakes, and marshes nationwide. It is not strongly associated with a single dao di (terroir) region the way many herbs are. Major producing areas include Anhui, Jiangsu, Zhejiang, and Hubei provinces. Because the plant is so widespread and abundant, it is typically wild-harvested rather than cultivated. Fresh Lu Gen is preferred in clinical use, and proximity to clean water sources is considered important for quality.

Harvesting Season

Can be harvested year-round; traditionally preferred in late spring, early summer, or autumn. Fresh rhizome (鲜芦根) is clinically preferred over the dried form.

Supplier Information

Treasure of the East

Loading supplier information...

Loading supplier attributes...

Miscellaneous Info

No additional information available

Usage & Safety

How to use this herb and important safety information

Important Medical Disclaimer

The information provided here is for educational purposes only and is not intended as medical advice or to replace consultation with a qualified healthcare professional. This herb is a dietary supplement and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease.

Always consult with a qualified healthcare provider, particularly if you are pregnant, nursing, have a medical condition, or are taking other medications. Discontinue use and consult your healthcare provider if you experience any adverse reactions.

Recommended Dosage

Loading dosage information...

Instructions for safe storage and consumption

Loading storage and consumption information...

Traditional Dosage Reference

Standard

15-30g (dried); fresh product double the dose, or juice the fresh rhizome

Maximum

Up to 60g of dried product (or equivalent fresh product) when used to promote rash eruption or in acute febrile conditions, under practitioner guidance

Notes

Fresh Lu Gen (鲜芦根) is preferred over the dried form for generating fluids and clearing Heat, as its juice content is much higher and its cooling, fluid-nourishing action is stronger. When using fresh product, the dosage is generally double that of the dried (30 to 60g or more). For mild Heat with thirst, standard doses of 15 to 30g dried are sufficient. For lung abscess (肺痈) patterns, larger doses are used, often combined with Yi Yi Ren, Dong Gua Ren, and Tao Ren in formulas like Wei Jing Tang. When used specifically to promote rash eruption in children, doses up to 60g may be employed. Fresh rhizome can also be juiced directly and taken as a beverage.

Toxicity Classification

Non-toxic

Lu Gen is classified as non-toxic in both classical and modern sources. The Yao Xing Lun (药性论) explicitly states it is "wu du" (无毒, non-toxic). No toxic components have been identified. A 2019 genotoxicity study found no mutagenic or genotoxic effects from aqueous reed rhizome extract in standard in vitro and in vivo test batteries. The only concern with excessive or prolonged use is damage to Yang Qi due to its cold nature, which may manifest as fatigue, poor appetite, or loose stools. These are functional effects of overcooling, not toxicity in the pharmacological sense.

Contraindications

Caution

Spleen and Stomach deficiency-Cold (脾胃虚寒). Lu Gen is sweet and cold in nature. People with weak, cold digestive systems who tend toward loose stools, poor appetite, or abdominal coldness should avoid this herb, as it can further damage Spleen and Stomach Yang.

Avoid

Vomiting or abdominal distension caused by Cold. The Ben Cao Jing Shu (本草经疏) specifically warns against using Lu Gen when vomiting or cholera-like symptoms are caused by Cold pathogen rather than Heat, as its cold nature would worsen the condition.

Caution

Prolonged high-dose use. Long-term or excessive use of this cold herb can injure Yang Qi, potentially leading to fatigue, reduced appetite, and loose stools.

Special Populations

Pregnancy

Generally considered safe at standard doses during pregnancy. Classical texts actually note Lu Gen's use for pregnant women. The Ri Hua Zi Ben Cao (日华子本草) records that it "treats pregnant women's heart heat" (好孕人心热), and the Ben Cao Jing Shu explains that "pregnant women with insufficient blood develop heart heat; its sweet, cold nature clears heat and settles the stomach." It has no known uterine-stimulating or blood-moving properties. However, as with all cold-natured herbs, prolonged heavy use should be avoided in pregnancy, particularly if the person has a cold constitution.

Breastfeeding

No specific contraindications for breastfeeding have been identified. Lu Gen is a mild, food-grade herb with sweet flavour and no known toxic components. Its cold nature means very high doses over long periods could theoretically affect milk production in mothers with underlying Spleen-Stomach Yang deficiency, but at standard doses it is generally regarded as safe during breastfeeding.

Pediatric Use

Lu Gen is considered a mild, non-toxic herb suitable for children. Dosage should be reduced proportionally based on age and body weight, typically one-third to one-half of adult dosage for young children. It is often included in pediatric formulas for childhood febrile illness with thirst and irritability, and for promoting the eruption of rashes (such as measles) when they fail to surface properly. Its sweet taste and gentle action make it well-tolerated by children.

Drug Interactions

No well-documented pharmacological drug interactions have been reported for Lu Gen. Its known active constituents include polysaccharides, asparagine, coixol, ferulic acid, p-coumaric acid, and B vitamins. Pharmacological research has demonstrated mild sedative, analgesic, and blood sugar-lowering effects. Based on these properties:

  • People taking hypoglycemic medications should be aware of the herb's mild blood sugar-lowering activity, though clinically significant interaction at standard doses is unlikely.
  • The mild sedative action observed in animal studies suggests theoretical caution when combined with central nervous system depressants, though this has not been confirmed clinically.

Overall, Lu Gen is pharmacologically mild and no clinically significant drug interactions have been established in the literature.

Dietary Advice

When taking Lu Gen for Heat-related conditions, it is best to avoid hot, spicy, greasy, or deep-fried foods, which can generate further internal Heat and counteract the herb's cooling effect. Light, easily digestible foods such as congee, pear, watermelon, and mung bean soup complement its fluid-generating and Heat-clearing actions. Because Lu Gen is cold in nature, people with weak digestion should not combine it with excessive amounts of raw or cold foods to avoid further burdening the Spleen and Stomach.

Cautions & Warnings

Although this formula is typically safe for most individuals, it may cause side effects in some people. Pregnant women, nursing mothers, postpartum women, and those with liver disease should use the formula with caution.

As with any Chinese herbal remedy, it is advisable to seek guidance from a qualified TCM practitioner before beginning treatment.