Tree barks and root barksTonifyingCortex Eucommiae

Du Zhong (Eucommia Bark)

Q: What is Du Zhong? Is it the same as Eucommia leaf or Hou Po?

Official Du Zhong (杜仲) is the dried bark of Eucommia ulmoides . The pharmacopoeial name is Eucommiae Cortex . When snapped it shows fine, silvery, elastic rubber threads —the key identification mark. Eucommia leaf is another medicinal part, not a stand-in for the bark. Hou Po is Magnolia bark, acrid-warm to move Qi and dry damp, with no rubber silk. Thin fakes without threads are not authentic.

Q: What are the TCM properties and traditional uses of Du Zhong?

According to the Chinese Pharmacopoeia, Du Zhong is sweet and warm , enters the Liver and Kidney channels, and acts to tonify Liver and Kidney, strengthen sinews and bones, and calm the fetus . It is used for Liver-Kidney insufficiency, sore weak lumbar and knees, feeble sinews and bones, dizziness, spotting in pregnancy and fetal restlessness. Sweet-warm tonification of Liver and Kidney—Liver rules the sinews, Kidney rules the bones—strengthens the waist; it also secures Chong and Ren to calm the fetus.

Q: How do raw and salt-fried Du Zhong differ?

Raw bark leans to benefiting the Liver and easing the sinews, and was also used for wind-damp impediment. Salt-fried Du Zhong is fried in brine until the threads break and the surface is scorched black; it is guided into the Kidney, preferred for tonifying Liver-Kidney, strengthening sinews and bones and calming the fetus, and extracts more readily. Deficiency lumbar pain and insecure fetal origin usually use the salt-fried form. Name raw or salt-fried on the script.

Q: What is the usual dosage of Du Zhong?

Pharmacopoeial and clinical internal doses are commonly 6–10 g in decoction; it may also enter pills, powders or wine. Salt-fried shreds decoct with the rest of the formula. It is not a long-term high-dose “blood-pressure tea.” Reduce or avoid it in Yin-deficiency fire and excess heat.

Q: What are the contraindications? Can it be used in pregnancy?

Use caution in Yin-deficiency fire. Sweet-warm yang-assisting dries people with dry mouth, tidal heat and night sweat, or interior excess fire. Tradition lists an aversion to Xuanshen. Calming the fetus is for Liver-Kidney insufficiency and insecure Chong-Ren with spotting and restlessness—not every threatened miscarriage. Qi-fall and heat harassing Chong-Ren need different methods. Worsening bleeding is an emergency.

Q: How do you choose and store Du Zhong?

Choose thick, large bark with the rough outer cortex scraped, a dark-purple inner face, and many elastic rubber threads when snapped . Salt-fried pieces are scorched black, less elastic, and slightly salty. Store ventilated and dry. Thin bark without silk, mold, or anonymous “leaf tea” cannot stand in for official bark. The label should read Du Zhong or salt-fried Du Zhong. Buy from a regulated source.

A practical guide to Du Zhong: what it is, how Traditional Chinese Medicine uses it, the classical formulas it appears in, and who should be careful with it.

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Last reviewed Sep 25, 2026

Quick Facts

Latin Name	Cortex Eucommiae
Chinese Name & Pinyin	杜仲 · Du Zhong
Medicinal Part	Tree barks and root barks
The herb	Du Zhong is the dried bark of Eucommia ulmoides. Broken pieces show white silk-like threads. The leaf is not this official drug. Common forms: raw and salt-fried.
Nature and channels	Sweet, warm. Enters the Liver and Kidney. Sweetness tonifies. Warmth assists Liver and Kidney yang.
Pharmacopoeia line	Tonifies Liver and Kidney. Strengthens sinews and bones. Calms the fetus. Used for Liver–Kidney deficiency, sore low back and knees, weak sinews and bones, dizziness, spotting in pregnancy, and restless fetus.
Pattern cues	Sore weak loins and knees. Frail legs. Dizziness and tinnitus. Restless fetus. Pale tongue. Weak pulse.
In this article	Raw versus salt-fried Du Zhong. How it differs from Sang Ji Sheng, Xu Duan, and Huai Niu Xi. Why yin-deficiency fire is a stop sign. Who should skip it.

What Is Du Zhong?

Du Zhong (杜仲; Dù Zhòng; Latin: Eucommiae Cortex; English: Eucommia bark) is the dried bark of Eucommia ulmoides Oliv. In Chinese medicine it is a yang-tonifying herb. It is sweet and warm, enters the Liver and Kidney channels, and its core actions are to tonify Liver and Kidney, strengthen sinews and bones, and calm the fetus. Broken bark shows silvery rubber threads. That is a key sign of the genuine piece. It is not Du Zhong leaf tea. The leaf may be drunk as tea; it is not equal to the official bark. It is not Huai Niu Xi. Huai Niu Xi conducts blood downward and also moves blood. Du Zhong warms and tonifies Liver and Kidney and calms the fetus without breaking blood.

It is used most often for three patterns:

Sore weak low back and knees, frail sinews and bones — Liver–Kidney deficiency, weak spine, tired legs
Dizziness from Liver–Kidney deficiency — dizziness, tinnitus, sore low back
Restless fetus / spotting in pregnancy — Kidney deficiency failing to hold the fetus

Raw Du Zhong tonifies more directly. Salt-fried Du Zhong is guided to the Kidney and is used more to strengthen the low back and calm the fetus. The usual decoction dose is 6–10 g. Yin-deficiency fire—dry mouth, red tongue, tidal heat—is a poor match used alone. Sweet warmth assists yang. Not every low-back ache is a daily “waist tea.”

After long standing or sitting, with age, or with lumbar ache in pregnancy, Liver–Kidney weakness in the low back and knees is common. Du Zhong is sweet-warm. It tonifies and firms, which is why it is often paired with Sang Ji Sheng and Xu Duan. It tonifies more than it moves. Damp-heat low-back pain that burns and refuses pressure gets worse if more warmth is added.

Du Zhong is not a catch-all for low-back pain, and it does not replace pattern-based fetal calming. In damp-heat painful obstruction or yin-deficiency fire, using it alone can assist heat and damage yin. Raw or salt-fried, and whether to pair it with mulberry mistletoe and dipsacus, should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Du Zhong: Materia Medica Profile

Identification & Quality Standard

Cortex Eucommiae

Botanical Origin

The dried tree barks of Eucommia ulmoides Oliv.(Eucommiaceae).

Production Regions

Primarily produced in the Chinese provinces of Guizhou, Sichuan, Shaanxi, Hubei.

Quality Requirements

Superior medicinal material has large and thick cortex, cleaned rough skin, externally yellowish-brown, inner surface is black-brown and lustrous, large amount of white threads.

Macroscopic Features

Flat board shape or roll shape, uneven thickness and size, often about 3~10mm thick, 40~100cm long. Externally grayish-brown, rough, irregular longitudinal grooves and horizontally-oriented oblique square lenticels, some has pale gray lichen patches. Commercial material has the outer rough skin removed and is externally pale brown and relatively smooth. Inner surface is smooth and dark purple. Brittle and easily broken; fractured surface has silvery-white connected silk-like threads that are thin and dense, with slightly elasticity. faint odor; taste slightly bitter; gluey residue when chewed.

Traditional Origins and Quality Identification

The most prized, high-quality bark traditionally comes from regions like Sichuan, Guizhou, and Yunnan.

Quality Traits: Good quality bark is flat or slightly curled, with a dark purple, smooth interior. When you snap it in half, it reveals a signature feature: fine, silvery-white, incredibly elastic rubbery threads connecting the broken pieces.
Raw vs. Prepared: Raw Du Zhong (Eucommia Bark) is very hard, making it difficult to extract its active ingredients during boiling. The charred version, Du Zhong Tan (Charcoal-prepared Eucommia Bark), is often used specifically to help stop bleeding.
Imitations: Be careful not to confuse it with the bark of the Silk Cotton Tree, which looks similar but is thinner, lighter in color, and has far fewer rubbery threads.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Sweet; WarmLiverKidney

1. Historical Records

Shen Nong's Herbal Classic: Ancient texts noted it was excellent for lower back pain, replenishing core energy, and strengthening bones and willpower.
Compendium of Materia Medica: Later classics explained that because it is sweet, warm, and moist, it perfectly enters the Liver to support the Kidneys.

2. Evolution of Clinical Understanding

For centuries, TCM doctors have universally agreed on its power to treat Liver and Kidney deficiency—which often shows up as a weak, sore lower back and wobbly knees. However, modern and historical masters emphasize that it is not a cure-all. Because it is a warming herb, people with "Yin deficiency and excessive fire" (showing signs of internal heat and dryness) should use it with caution. TCM is all about precision and matching the herb to the exact body type.

Core Efficacies & Traditional Applications

Traditional Functions

Supplements the live and kidney, strengthens sinew and bone, calms the fetus. Apply to aching pain in the loins and knees, weakness of legs and knees, drenching and unsmooth urination, vaginal dampness and itch, fetal leakage and abortion, restless fetal movement, hypertension.

1. Primary Focus: Tonifying the Liver and Kidneys

Traditional Efficacy: One of the most important functions of Du Zhong (Eucommia Bark) is its ability to deeply nourish and strengthen the Liver and Kidneys.
Target Symptoms: It is primarily used for syndromes caused by Liver and Kidney deficiency, which typically present as soreness and weakness in the lower back and knees, dizziness, ringing in the ears (tinnitus), and reproductive issues like impotence.
Common Combinations: To maximize its strengthening effects, it is often paired with herbs like Sang Ji Sheng (Mulberry Mistletoe Stem), Xu Duan (Teasel Root), and Niu Xi (Achyranthes Root).
When to Avoid Self-Use: If you have a constitution of "Yin deficiency with excessive fire" (characterized by internal heat, night sweats, and a dry mouth), you should not use this on your own, as its warming nature can aggravate the internal heat.

2. Secondary Focus: Strengthening Bones and Sinews

Traditional Efficacy: Du Zhong (Eucommia Bark) is excellent at improving the resilience and strength of bones, tendons, and ligaments.
Target Symptoms: Commonly used when people experience soft, weak bones, frail sinews, or general fatigue and difficulty when walking.
Common Combinations: It is frequently combined with Shu Di (Prepared Rehmannia Root), Shan Zhu Yu (Asiatic Cornelian Cherry Fruit), and Gou Qi Zi (Goji Berry) to boost its bone-strengthening power.
When to Avoid Self-Use: People with "excess" or "heat" syndromes (acute inflammation or robust heat symptoms) should avoid it to prevent trapping the illness in the body.

3. Common Single-Herb Pairings

A classic synergistic pairing is Du Zhong (Eucommia Bark) and Niu Xi (Achyranthes Root). Du Zhong acts to tonify the Liver and Kidneys, while Niu Xi focuses on strengthening the bones and directing the energy downward. Together, they are highly effective for treating lower back and knee weakness. However, this combination requires a TCM practitioner to properly assess your body type before use.

Modern Research

Modern research offers useful context, but Traditional Chinese Medicine prescribes on whole-pattern diagnosis rather than isolated compounds.

1. Key Chemical Components

Modern science has found that Du Zhong (Eucommia Bark) is packed with unique compounds, including eucommia rubber, aucubin, chlorogenic acid, and various flavonoids.

Lab Findings: Test-tube studies show it has antioxidant and anti-inflammatory properties. Animal studies suggest it may help repair liver and kidney damage and improve bone density.
Note: These are isolated findings and still require extensive human clinical trials to confirm exact dosages and effects.

2. Modern Pharmacological Focus

Today, researchers are highly interested in how Du Zhong (Eucommia Bark) affects the cardiovascular and immune systems. Studies are exploring its potential to help regulate blood pressure, balance blood lipids, and boost overall immunity.

3. Limitations of Modern Research

When reading about modern studies on traditional herbs, keep these important boundaries in mind:

Animals Aren't Humans: Promising results in a lab rat do not automatically translate to human healing.
Extracts vs. Whole Herbs: Taking an isolated chemical extract is very different from drinking a traditionally boiled whole-herb decoction.
Inconsistent Methods: Different studies use different dosages and preparation methods, making it hard to draw universal conclusions.
The Power of Synergy: In TCM, you cannot judge an herb by one single chemical. The healing power of Du Zhong (Eucommia Bark) comes from how all of its natural components work together in the human body.

Comparing Similar Herbs

1. Common Ground

Both Du Zhong (Eucommia Bark) and Xu Duan (Teasel Root) are famous for tonifying the Liver and Kidneys and strengthening bones. They are both go-to herbs for lower back and knee weakness, often appear together in formulas, and require careful dosing based on a person's constitution.

2. Core Differences

Nature: Du Zhong is sweet and warm, making it a stronger warming tonic. Xu Duan is bitter, pungent, and slightly warm, making its nature much milder.
Clinical Focus: While Du Zhong focuses heavily on nourishing the organs, Xu Duan excels at healing trauma and bone fractures.
Energy Movement: Du Zhong primarily directs its nourishing energy to the lower body (Kidneys). Xu Duan not only nourishes but also actively moves the blood to clear blockages.
Target Symptoms: Du Zhong is best for clear signs of deficiency (like a chronically weak back). Xu Duan is widely used in orthopedics for physical injuries and broken bones.
Cautions: Du Zhong must be used cautiously by those with Yin deficiency and internal heat. Xu Duan should be avoided by those with weak digestion or diarrhea.

3. One-Sentence Summary

Du Zhong (Eucommia Bark) is the master of warming and tonifying the Liver and Kidneys, while Xu Duan (Teasel Root) is the specialist for healing bone injuries; despite their similarities, they cannot simply replace one another.

Classical Formulas Containing Du Zhong

Du Huo Ji Sheng Tang

獨活寄生湯

Formula CategoryWind-Damp Dispelling FormulasPrimary PatternDampnessPrimary FunctionDispel wind-damp, stop bi pain, tonify Liver and Kidney, nourish Qi and bloodRelated ConditionsLow Back Pain·Joint Discomfort·Numbness in Limbs

View Formula Profile Read Complete Guide

Huan Shao Dan

還少丹

Formula CategoryYang-Tonifying FormulasPrimary PatternKidney Yang DeficiencyPrimary FunctionTonify Kidney, replenish essence, nourish blood, benefit QiRelated ConditionsLow Libido·Fatigue & Low Energy

View Formula Profile Read Complete Guide

You Gui Wan

右歸丸

Formula CategoryYang-Tonifying FormulasPrimary PatternKidney Yang DeficiencyPrimary FunctionWarm and tonify Kidney Yang, fill essence and marrowRelated ConditionsCold Limbs·Fatigue & Low Energy·Low Libido·Frequent Nocturia

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Tian Ma Gou Teng Yin

天麻鉤藤飲Assistant

Formula CategoryLiver-Wind Extinguishing FormulasPrimary PatternLiver FirePrimary FunctionCalm Liver Yang, extinguish internal wind, clear heatRelated ConditionsHeadache·Dizziness & Vertigo·Tinnitus·Anxiety Restlessness

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+1 more

San Bi Tang

三痹湯

Formula CategoryWind-Damp Dispelling FormulasPrimary PatternDampnessPrimary FunctionDispel wind-damp, tonify Qi and blood, ease bi painRelated ConditionsJoint Discomfort·Low Back Pain·Numbness in Limbs

View Formula Profile Read Complete Guide

Formulas vs. Single Herbs

Synergy is Key: A formula is a balanced team. The healing power comes from how the herbs interact, so a single herb cannot simply replicate a full formula's effects.
Holistic Balance: The exact dosage and combination in a formula affect the entire body. Never try to mix or alter these formulas at home based on internet articles.

Diet & Daily Home Use

1. Home Recipes and Teas

Du Zhong Pig Kidney Soup

Ingredients: 15g Du Zhong (Eucommia Bark), 1 pig kidney.
Preparation: Wash the herb. Clean the pig kidney, slice it open, and remove the white fascia. Stuff the herb inside the kidney, tie it shut with string, and stew it in a pot with water until the kidney is tender.
Best For: Individuals with Liver and Kidney deficiency experiencing a weak lower back and knees.
Cautions: People with high cholesterol should not consume this frequently. Recommended 1-2 times a week. Note: This is a medicinal dish, not a daily vegetable, and should be consumed in moderation.

2. Decoction and Processing Differences

Raw Du Zhong (Eucommia Bark) is very hard, making it difficult to extract its active ingredients, so it usually requires pre-boiling (cooking it longer than other herbs). The processed version, Du Zhong Tan (Charcoal-prepared Eucommia Bark), is specifically used to enhance its ability to stop bleeding. When making a decoction at home, soak the herb for about 30 minutes, bring it to a rolling boil on high heat, and then simmer on low heat. Always follow your doctor's specific instructions regarding the prepared form.

3. Dosage and Usage Cycle

The standard clinical dosage is typically 6 to 10 grams. Dietary and tea dosages are usually smaller. Continuous, long-term use is not recommended as it may cause adverse reactions. Vulnerable populations (pregnant women, children, the elderly, or those with impaired organ function) must consult a physician before use.

Contraindications & Safety Warnings

1. Inappropriate Populations

You should avoid Du Zhong (Eucommia Bark) if you fall into any of these categories:

Those with Yin deficiency and excessive fire
Pregnant and nursing women (unless explicitly prescribed)
Children and the elderly (without supervision)
Individuals with liver or kidney function abnormalities
Those allergic to the plant Always consult a professional rather than assuming an herb is "absolutely safe."

2. Herb-Drug Interactions

Du Zhong (Eucommia Bark) may interact with certain Western medications. For example, it can enhance the effects of blood pressure medications. While normal food combinations are generally fine, if you are on any prescription drugs, you must consult your doctor or pharmacist to avoid dangerous interactions.

3. Adverse Reactions and Overdose Risks

Taking too much can lead to symptoms like nausea, vomiting, and dizziness. If you experience severe discomfort, allergic reactions, persistent vomiting, difficulty breathing, or rapid worsening of symptoms, stop using it immediately and seek emergency medical care.

Frequently Asked Questions About Du Zhong

What is Du Zhong? Is it the same as Eucommia leaf or Hou Po?

Official Du Zhong (杜仲) is the dried bark of Eucommia ulmoides. The pharmacopoeial name is Eucommiae Cortex. When snapped it shows fine, silvery, elastic rubber threads—the key identification mark. Eucommia leaf is another medicinal part, not a stand-in for the bark. Hou Po is Magnolia bark, acrid-warm to move Qi and dry damp, with no rubber silk. Thin fakes without threads are not authentic.

What are the TCM properties and traditional uses of Du Zhong?

According to the Chinese Pharmacopoeia, Du Zhong is sweet and warm, enters the Liver and Kidney channels, and acts to tonify Liver and Kidney, strengthen sinews and bones, and calm the fetus. It is used for Liver-Kidney insufficiency, sore weak lumbar and knees, feeble sinews and bones, dizziness, spotting in pregnancy and fetal restlessness. Sweet-warm tonification of Liver and Kidney—Liver rules the sinews, Kidney rules the bones—strengthens the waist; it also secures Chong and Ren to calm the fetus.

How do raw and salt-fried Du Zhong differ?

Raw bark leans to benefiting the Liver and easing the sinews, and was also used for wind-damp impediment. Salt-fried Du Zhong is fried in brine until the threads break and the surface is scorched black; it is guided into the Kidney, preferred for tonifying Liver-Kidney, strengthening sinews and bones and calming the fetus, and extracts more readily. Deficiency lumbar pain and insecure fetal origin usually use the salt-fried form. Name raw or salt-fried on the script.

What is the usual dosage of Du Zhong?

Pharmacopoeial and clinical internal doses are commonly 6–10 g in decoction; it may also enter pills, powders or wine. Salt-fried shreds decoct with the rest of the formula. It is not a long-term high-dose “blood-pressure tea.” Reduce or avoid it in Yin-deficiency fire and excess heat.

What are the contraindications? Can it be used in pregnancy?

Use caution in Yin-deficiency fire. Sweet-warm yang-assisting dries people with dry mouth, tidal heat and night sweat, or interior excess fire. Tradition lists an aversion to Xuanshen. Calming the fetus is for Liver-Kidney insufficiency and insecure Chong-Ren with spotting and restlessness—not every threatened miscarriage. Qi-fall and heat harassing Chong-Ren need different methods. Worsening bleeding is an emergency.

Can Du Zhong treat lumbar pain, calm the fetus and lower blood pressure?

Sore weak lumbar and knees from Liver-Kidney depletion are its core job, often with Dipsacus, Psoralea and Achyranthes. Fetal restlessness and pregnancy spotting from vacuity without securing may join mistletoe, Dipsacus and dodder. Modern work shows a blood-pressure effect, but dizziness still needs a Liver-Yang versus Liver-Kidney read; Eucommia is not a stand-alone antihypertensive. Acute sprain, nerve compression and preeclampsia need proper examination.

Can Du Zhong be steeped daily as a Kidney tonic tea?

Not as an unlimited four-season tea. Warm tonification suits cold-deficiency lumbar ache; lingering use in Yin-deficiency heat with bitter mouth and dry stool can assist fire. Blood pressure, fetal calming and lumbar pain should follow a pattern, in a course or a formula. Bark is a limited resource; unlabeled “Eucommia tea” from non-bark parts is not a substitute for official slices.

How do you choose among Du Zhong, Xu Duan, Sang Ji Sheng and Niu Xi?

Eucommia is sweet-warm: tonifies Liver-Kidney, strengthens sinews and bones, calms the fetus. Dipsacus is bitter-acrid and slightly warm: tonifies and also moves Blood and knits injury. Mistletoe is bitter-sweet and neutral: dispels wind-damp, tonifies Liver-Kidney, calms the fetus and can nourish Blood. Achyranthes invigorates and directs Blood downward—Huai more tonic, Chuan more moving. Vacuity lumbar ache favors Eucommia and Dipsacus; wind-damp adds mistletoe; stasis that should descend favors Achyranthes. They may be paired; Cold, Heat, stasis and vacuity still differ.

Which herbs is Du Zhong combined with? What are the representative formulas?

With Psoralea and walnut for Kidney-deficiency lumbar pain it appears in Qing E Wan. Liver-Kidney insufficiency with lumbar impediment joins Pubescent Angelica, mistletoe and Achyranthes, as in Du Huo Ji Sheng Tang. Fetal calming joins Dipsacus, mistletoe and dodder. Name salt-fried or raw; pregnancy formulas must be written by an experienced practitioner.

How do you choose and store Du Zhong?

Choose thick, large bark with the rough outer cortex scraped, a dark-purple inner face, and many elastic rubber threads when snapped. Salt-fried pieces are scorched black, less elastic, and slightly salty. Store ventilated and dry. Thin bark without silk, mold, or anonymous “leaf tea” cannot stand in for official bark. The label should read Du Zhong or salt-fried Du Zhong. Buy from a regulated source.

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Medical Disclaimer — This article is provided for educational purposes only and describes traditional Chinese medicine concepts. It is not medical advice, and it is not intended to diagnose, treat, cure or prevent any disease. Always consult a qualified practitioner before using any herb, particularly if you are pregnant, nursing, taking medication or managing a diagnosed condition.