Herb

Hu Zhang

Bushy knotweed rhizome | 虎杖

Also known as:

Giant Knotweed , Bai Ji Li

Hu Zhang

Product appearance may vary from images shown

Properties

Blood-invigorating and stasis-dispelling herbs (活血化瘀药) · Slightly Cool

Traditionally supports*

Liver Health Joint and Muscle Health Menstrual Health Respiratory Health Skin 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

$27.00 ($0.27/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

Hu Zhang (Japanese knotweed rhizome) is a versatile herb best known for clearing Dampness-Heat from the Liver and Gallbladder, making it widely used for jaundice and liver complaints. It also moves stagnant Blood to relieve pain from injuries or menstrual problems, and calms coughs caused by Lung Heat. Rich in resveratrol and emodin, it has attracted modern research interest for its anti-inflammatory, liver-protective, and cardiovascular benefits.

Herb Category

Blood-invigorating and stasis-dispelling herbs (活血化瘀药) Herbs that clear Heat and dry Dampness (清热燥湿药)

Main Actions

  • Clears Damp-Heat and Resolves Jaundice
  • Clears Heat and Resolves Toxicity
  • Invigorates Blood and Dispels Stasis
  • Alleviates Pain
  • Resolves Phlegm and Stops Cough
  • Promotes Bowel Movement

How These Actions Work

'Clears Dampness-Heat and reduces jaundice' refers to Hu Zhang's ability to drain accumulated Dampness and Heat from the Liver and Gallbladder, which makes it a go-to herb for conditions involving yellowing of the skin and eyes (jaundice). It promotes the normal flow of bile and helps the body eliminate excess fluid and heat through urination. This is its primary listed action in the Chinese Pharmacopoeia, and it is often combined with Yin Chen Hao (Artemisia) for this purpose.

'Clears Heat and resolves toxins' means Hu Zhang can combat infections and inflammatory conditions caused by Heat-toxin. This covers skin abscesses, boils, sore throat, and even burns and scalds. Applied externally as a paste or wash, it promotes wound healing. Pharmacological research has shown it contains emodin and resveratrol, which demonstrate antimicrobial and anti-inflammatory properties.

'Invigorates Blood and dispels stasis' describes how Hu Zhang gets stuck Blood moving again. This is especially relevant for women with absent or painful periods caused by Blood stasis, as well as for traumatic injuries with bruising and swelling. Classical texts from the Ming Bie Lu onward have noted its power to break up stagnant Blood and open the menstrual flow.

'Transforms Phlegm and stops coughing' refers to Hu Zhang's action on the Lungs. Because it enters the Lung channel and has a bitter, slightly cold nature, it can descend Lung Qi and clear Lung Heat, making it useful for coughs with thick yellow phlegm.

'Unblocks the bowels' is related to Hu Zhang's content of anthraquinone compounds (similar to Da Huang / Rhubarb). At sufficient doses, it has a gentle laxative effect, helpful for constipation caused by Heat accumulation in the intestines.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony that reveal what's out of balance in the body. Hu Zhang 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 Hu Zhang addresses this pattern

Hu Zhang's bitter taste drains Dampness and its slightly cold nature clears Heat. Because it enters the Liver and Gallbladder channels directly, it targets the root pathomechanism of this pattern: Dampness and Heat steaming in the Liver-Gallbladder system, obstructing bile flow and producing jaundice. Its ability to promote urination helps drain the Dampness downward and out of the body, while its Heat-clearing action addresses the inflammatory component that drives the yellowing, dark urine, and hypochondriac fullness typical of this pattern.

A practitioner would look for one or more of these signs

Jaundice

Yellow discoloration of skin and eyes from Dampness-Heat

Dark Urine

Scanty dark yellow urine

Hypochondriac Pain

Distension and pain below the ribs

Thin Vaginal Discharge

Yellow, foul-smelling vaginal discharge from Dampness-Heat pouring downward

TCM Properties

Temperature

Slightly Cool

Taste

Bitter (苦 kǔ)

Channels Entered
Liver Gallbladder Lungs
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 Hu Zhang root consists of thick, stout pieces that are firm and hard. The exterior bark should be brown to dark brown with longitudinal wrinkles and rootlet scars. In cross-section, the cortex is thin and the wood portion is broad and brownish-yellow with clearly visible radial ray lines. The cortex and wood layers should separate relatively easily. The rhizome pith should show visible partitions or hollow chambers. The material should feel heavy and solid. The aroma is faint, and the taste should be slightly bitter and astringent. The best material is described as thick, solid, and distinctly yellow in the cross-section. Avoid pieces that are overly thin, lightweight, darkened throughout, or show signs of mould or insect damage.

Primary Growing Regions

Hu Zhang is widely distributed across China, with key production areas in the southwest (Sichuan, Yunnan, Guizhou), south-central China (Hunan, Hubei), and eastern regions (Zhejiang, Jiangxi, Anhui, Jiangsu, Fujian). It also grows in Shaanxi (southern), Gansu (southern), Guangxi, Guangdong, and Hebei. Classical sources note it is found in Fenzhou (Shanxi), Yuezhou (Zhejiang), and Chuzhou (Anhui). It also occurs natively in Korea and Japan. The best quality material traditionally comes from the mountainous southwestern and south-central provinces where wild populations grow in moist hillside thickets.

Harvesting Season

Spring or autumn. Roots propagated by division are harvested from the second year onward; seed-propagated plants from the third year. The roots are dug up, cleaned of rootlets, washed, sliced into short segments or thick pieces while fresh, and sun-dried.

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

9-15g

Maximum

Up to 30g in acute conditions such as severe Damp-Heat jaundice or painful obstruction, under practitioner supervision. Some historical formulas used larger amounts for Blood stasis obstruction (amenorrhea, abdominal masses), but modern clinical practice generally does not exceed 30g in decoction.

Notes

Use lower doses (9 to 15g) for clearing Damp-Heat, resolving jaundice, and transforming phlegm to stop cough. Use moderate to higher doses (15 to 30g) for invigorating Blood, dispersing stasis, and treating amenorrhea, painful obstruction, or traumatic injury. For external use (burns, sores, skin infections), the herb can be ground into powder and applied as a paste, or a concentrated decoction can be used as a wash. A classical dosage study found that Hu Zhang's Heat-clearing and detoxifying effects are best expressed at smaller doses (up to 30g), while its Blood-moving effects require moderate doses. Excessive dosage may cause gastrointestinal irritation due to the emodin and tannin content.

Processing Methods

Processing method

The raw sliced Hu Zhang is sprinkled with yellow rice wine (Huang Jiu), allowed to absorb the wine thoroughly, then stir-fried over gentle heat until dry.

How it changes properties

Wine processing enhances Hu Zhang's Blood-invigorating and channel-opening actions, directing its effects more strongly to the sinews and collaterals. It also moderates the herb's cold nature slightly, making it less likely to upset digestion. The Blood-moving effect becomes stronger while the Dampness-clearing and Heat-clearing actions become secondary.

When to use this form

Preferred for Wind-Damp Bi syndrome with joint and muscle pain, traumatic injuries, Blood stasis amenorrhea, and conditions where the primary goal is moving Blood rather than clearing Dampness-Heat. Also gentler on the Stomach for patients with weak digestion.

Toxicity Classification

Non-toxic

Hu Zhang is classified as non-toxic in the Chinese Pharmacopoeia at standard doses. However, it contains emodin and other anthraquinone derivatives, tannins, and multiple phenolic compounds. Excessive dosage may irritate the gastrointestinal mucosa, leading to nausea, vomiting, abdominal pain, or diarrhea. Animal toxicity studies on isolated polydatin (the glycoside form of resveratrol) showed that high intraperitoneal doses could cause liver cell necrosis, peritoneal inflammation, and bone marrow changes in rats, but these effects occurred at doses far exceeding normal therapeutic use. At standard oral doses in decoction (9 to 15g), Hu Zhang has a long track record of safe clinical use.

Contraindications

Avoid

Pregnancy. Hu Zhang is a Blood-invigorating herb with a bitter, cold nature. Classical sources including the Ben Cao Gang Mu explicitly state that pregnant women should not take it, as its Blood-moving and downward-draining properties may disturb the fetus or cause uterine contractions.

Caution

Spleen and Stomach deficiency with cold. The bitter, slightly cold nature of Hu Zhang can further damage a weak digestive system, potentially worsening loose stools, poor appetite, or abdominal pain in patients with cold-deficiency patterns.

Caution

Absence of Blood stasis or Damp-Heat. Since Hu Zhang is strongly clearing and Blood-moving, it should not be used long-term or in high doses in patients without genuine Heat or stasis, as it may injure Qi and Blood.

Caution

Heavy menstrual bleeding or active hemorrhage without Blood stasis. Because Hu Zhang invigorates Blood and disperses stasis, it may worsen bleeding that is not caused by stasis obstruction.

Caution

Excessive dosage. Hu Zhang contains emodin, tannins, and other phenolic compounds. Overconsumption can irritate the stomach lining and cause nausea, vomiting, or diarrhea.

Special Populations

Pregnancy

Contraindicated. Hu Zhang is a Blood-invigorating and stasis-dispersing herb with a slightly cold, bitter nature. Multiple classical sources explicitly warn against its use in pregnancy. The Ben Cao Gang Mu states: "Pregnant women must not take it" (有孕人勿服). The herb's active compounds, including emodin (an anthraquinone with laxative and uterine-stimulating properties) and resveratrol, may promote uterine contractions and disturb fetal development. Emodin has shown embryotoxic potential in animal studies. Hu Zhang should be strictly avoided throughout pregnancy.

Breastfeeding

Caution advised. Although no specific classical prohibitions exist for breastfeeding, Hu Zhang contains emodin and other anthraquinone compounds that are known to pass into breast milk (as demonstrated with related anthraquinone-containing herbs such as Da Huang). These compounds may cause loose stools or gastrointestinal irritation in the nursing infant. The slightly cold nature of the herb could also potentially affect lactation in women with underlying Spleen deficiency. Use only under practitioner guidance, and prefer alternative herbs when possible during breastfeeding.

Pediatric Use

Not commonly used in paediatric formulas. If prescribed for children by a qualified practitioner, dosages should be proportionally reduced based on age and body weight (typically one-third to one-half of the adult dose for older children). The herb's bitter, cold nature and Blood-moving properties make it unsuitable for young children or infants. The anthraquinone content (emodin) may cause diarrhoea, so bowel function should be monitored closely. Avoid prolonged use in children.

Drug Interactions

Anticoagulant and antiplatelet medications (warfarin, heparin, aspirin, clopidogrel): Hu Zhang invigorates Blood and disperses stasis. Its active compound resveratrol has demonstrated antiplatelet aggregation effects in pharmacological studies. Concurrent use with anticoagulant or antiplatelet drugs may increase bleeding risk. Monitoring of coagulation parameters is advised.

Antidiabetic medications: Resveratrol from Hu Zhang has shown blood-glucose-lowering effects in animal studies. Concurrent use with insulin or oral hypoglycaemic agents could theoretically potentiate hypoglycaemia. Blood sugar should be monitored.

Hepatically metabolised drugs (CYP450 substrates): Emodin and resveratrol have been shown to modulate certain cytochrome P450 enzymes in laboratory studies. This could theoretically alter the metabolism of drugs processed through the liver, though clinical significance at standard herbal doses is not fully established.

Laxatives: The anthraquinone emodin in Hu Zhang has mild laxative properties similar to those of Da Huang (rhubarb). Combining it with other laxatives or cathartic medications may result in excessive purging or electrolyte imbalances.

Dietary Advice

When taking Hu Zhang for Damp-Heat conditions (jaundice, urinary issues), avoid greasy, fried, and rich foods that generate Dampness and Heat. Avoid excessive alcohol. When using Hu Zhang for Blood stasis patterns, avoid cold and raw foods that could impede Blood circulation. Classical formulas for abdominal masses specifically warned against eating fresh fish and salt during treatment.

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.