Tree barks and root barksHeat-clearingCortex Ailanthi

Chun Gen Pi (Ailanthus Bark)

Q: What is Chun Gen Pi? Is it the same as Chun Pi, Chu Bai Pi or Chinese toon?

The current official name is usually Chun Pi : the dried root bark or stem bark of Ailanthus altissima (tree of heaven). The pharmacopoeial name is Ailanthi Cortex ; common synonyms are Chun Gen Pi and Chu Bai Pi. Most commercial material is Ailanthus. Xiang Chun (Toona sinensis) is a Meliaceae food tree whose young shoots are eaten; some regions also sell its bark as Chun Bai Pi, which is not the same official source. The Bencao Gangmu says fragrant red Toona bark enters the Blood and astringes, while pale foul Ailanthus bark enters the Qi and is more draining—they must be told apart. Toon sprouts are a vegetable, not a substitute for medicinal bark.

Q: What are the TCM properties and traditional uses of Chun Gen Pi?

According to the Chinese Pharmacopoeia, Chun Pi is bitter, astringent and cold , enters the Large Intestine, Stomach and Liver channels, and acts to clear heat and dry dampness, astringe to stop leukorrhea, stop diarrhea and stop bleeding . It is used for red-and-white vaginal discharge, damp-heat dysentery, chronic diarrhea and dysentery, bloody stool and uterine bleeding. Bitter-cold to clear damp-heat, astringent to secure collapse, it both dries lower-burner damp-heat and binds—an astringent heat-clearing herb, not a tonic.

Q: What is the difference between raw and bran-fried Chun Pi?

Raw bark is more bitter-cold and better to clear damp-heat when discharge or dysentery is still hot and foul. Bran-fried Chun Pi is a little less cold and is preferred to astringe diarrhea and bleeding in longer-standing cases. Neither form should bind too early while accumulation is still sitting in new dysentery. Name raw or bran-fried on the script.

Q: What is the usual dosage of Chun Gen Pi?

The pharmacopoeial decoction dose is 6–9 g (some texts allow 6–15 g); it may also enter pills or powders. Topically use a suitable amount as a wash or paste. Large doses can cause nausea. Reduce the dose for children and a weak Spleen-Stomach. Do not scrape garden Ailanthus or Toona bark and treat it as the official drug.

Q: Can Chun Gen Pi stop discharge, diarrhea and bleeding?

Yes, when the pattern is damp-heat . Foul red-and-white leukorrhea, damp-heat or lingering dysentery with pus and blood, intestinal-wind bloody stool and Blood-heat flooding often join Phellodendron, Coptis or Sanguisorba. Thin cold discharge, fifth-watch diarrhea and Qi-failing flooding are the wrong patterns. Acute bloody stool, high fever or severe pain needs medical care, not astringency alone.

Q: How do you choose and store Chun Gen Pi?

Choose root bark or irregular boards with a rough gray-black outer surface, a yellowish-white inner face, a faint odor and a bitter taste . Bran-fried pieces are slightly yellow. Store dry. Discard moldy or worm-eaten lots. Buy the official name Chun Pi or the synonyms Chun Gen Pi / Chu Bai Pi, and ask whether the source is Ailanthus or Toona. Use regulated slices; do not peel street-tree bark for medicine.

A practical guide to Chun Gen Pi: 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 Ailanthi
Chinese Name & Pinyin	椿根皮 · Chun Gen Pi
Medicinal Part	Tree barks and root barks
The herb	Official Chun Pi is the dried root bark or stem bark of Ailanthus altissima. Aliases include Chun Gen Pi and chu white bark. Xiang-chun bark is not this official item. Common forms: raw and bran-fried.
Nature and channels	Bitter, astringent, cold. Enters the Large Intestine, Stomach, and Liver. Bitterness dries dampness and clears heat. Astringency holds slippage.
Pharmacopoeia line	Clears heat and dries dampness. Astringes and stops leukorrhea. Stops diarrhea. Stops bleeding. Used for red-and-white vaginal discharge, damp-heat diarrhea and dysentery, chronic diarrhea and dysentery, bloody stool, and uterine flooding and spotting.
Pattern cues	Damp-heat diarrhea or dysentery. Lingering diarrhea. Yellow or red-and-white discharge. Bloody stool. Flooding and spotting. Yellow, greasy coating.
In this article	Chun Gen Pi versus culinary toon and versus Huang Bai and Bai Shao. Raw versus bran-fried. Dose, and who should skip it.

What Is Chun Gen Pi?

Chun Gen Pi (椿根皮) is the common alias for the official drug Chun Pi (椿皮; Chūn Pí; Latin: Ailanthi Cortex; English: tree-of-heaven bark). The official source is the dried root bark or stem bark of Ailanthus altissima (Mill.) Swingle. In Chinese medicine it is a heat-clearing, dampness-drying, astringent herb. It is bitter, astringent, and cold, enters the Large Intestine, Stomach, and Liver channels, and its core actions are to clear heat and dry dampness, astringe and stop vaginal discharge, stop diarrhea, and stop bleeding. It is not culinary toon. Toona sinensis (xiang chun) is a different plant; its young shoots are eaten as food. Toon bark is used in some regions, but it is not this official drug. Older texts called Ailanthus “chu” and Toona “chun.” One astringes, one is more sliding. The prescription should name which bark.

It is used most often for three patterns:

Damp-heat dysentery or diarrhea — abdominal pain, tenesmus, or lingering diarrhea
Red-and-white leukorrhea — yellow or mixed discharge with a foul odor
Bloody stool / flooding and spotting — bleeding from damp-heat injuring the collaterals

Raw Chun Pi is stronger at clearing heat and drying dampness. Bran-fried Chun Pi is less bitter-cold and is used more to astringe diarrhea and discharge. The usual decoction dose is 6–9 g. A cold weak spleen and stomach, or slippage with no damp-heat, is a poor match. Used too early while damp-heat is still pouring, astringency can trap the pathogen.

When damp-heat pours downward, dysentery, yellow thick leukorrhea, and bloody stool are common. Chun Gen Pi is bitter to dry dampness and astringent to hold what slips. It both clears and binds, which is why it is often paired with Huang Bai or Bai Shao. It clears and astringes more than it tonifies. Cold, watery diarrhea that likes warmth, or thin clear discharge, is the wrong picture.

Chun Gen Pi is not a catch-all for diarrhea or discharge. In deficiency-cold slippage, or while damp-heat is still raging, using it alone can trap the pathogen and injure the spleen. Raw or bran-fried should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Chun Gen Pi: Materia Medica Profile

Identification & Quality Standard

Cortex Ailanthi

Botanical Origin

The dried root bark of Ailanthus altissima (Mill.) Swingle (Simaroubaceae).

Production Regions

Primarily produced in the Chinese provinces of Hebei, Henan, Shandong and Jiangsu.

Quality Requirements

Superior medicinal material has a thick bark, yellowish inner surface, and a bitter taste.

Macroscopic Features

Quilled or irregular pieces of bark, 0.5~1.5cm thick. Externally greyish-yellow to yellowish-brown with lenticels; inner surface pale yellow; texture hard and brittle, fracture fibrous.

Traditional Sources and Quality Identification

The traditional Dao Di (authentic and premium) regions for this herb include Hebei, Shandong, and Henan provinces.

Appearance: High-quality bark appears as irregular flakes or rolls. The outside is greyish-yellow or yellowish-brown and rough, while the inside is pale yellow and smooth.
Texture & Taste: It is hard but brittle, breaking easily to reveal a fibrous inside. It has a mild scent and a bitter, astringent taste.
Processed vs. Raw: Raw bark is harder with a stronger scent. The stir-fried version becomes crispier with a darker color and a slightly altered, milder aroma.
Common Confusion: It can be confused with Ku Lian Gen Pi (Chinaberry Root Bark). However, Ku Lian Gen Pi is extremely bitter and carries a higher toxicity, making careful identification crucial.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Bitter, Astringent; ColdLarge IntestineLiver

1. Historical Herbology Records

Ben Cao Gang Mu (Compendium of Materia Medica) states: "Chun root white bark is bitter, astringent, cold in nature, and non-toxic. It treats diarrhea, intestinal wind (bleeding), women's heavy bleeding and abnormal discharge, as well as frequent urination."

2. Evolution of TCM Understanding

Over time, TCM practitioners have utilized this herb for different primary focuses:

Clearing Damp-Heat: Many use it to treat conditions caused by damp-heat sinking into the lower body (such as yellow, foul-smelling discharges).
Astringent Properties: Others emphasize its ability to bind the intestines, making it highly effective for chronic diarrhea or dysentery.
Caution: Because of its strongly cold nature, ancient doctors frequently warned against overusing it, as it can easily damage the body's digestive warmth (Spleen and Stomach Yang).

Core Efficacies & Traditional Applications

Traditional Functions

Clears heat, dries dampness, astringes the intestines, and stops bleeding and leukorrhea. Apply to damp-heat diarrhea or dysentery, metrorrhagia, and yellow leukorrhea.

1. Primary Focus: Clearing Heat and Drying Dampness

Traditional Efficacy: Clears internal damp-heat from the body.
Target Symptoms: Used for damp-heat sinking into the lower body, causing excessive, yellow, and foul-smelling vaginal discharge. It also treats damp-heat in the Spleen and Stomach, which leads to diarrhea, abdominal pain, a bitter taste in the mouth, and bad breath.
Common Combinations: Frequently paired with Huang Bo (Amur Cork Tree Bark) or Ku Shen (Sophora Root) to enhance its heat-clearing and dampness-drying effects.
Caution: Do not use without professional guidance if you have a "Spleen and Stomach deficiency-cold" constitution, as its cold nature can damage digestive warmth.

2. Secondary Focus: Binding the Intestines to Stop Diarrhea

Traditional Efficacy: Acts as a strong astringent to bind the intestines and stop excessive leakage.
Target Symptoms: Commonly used for chronic diarrhea or chronic dysentery, particularly when accompanied by mild, lingering abdominal pain or loss of bowel control.
Common Combinations: Often used alongside He Zi (Chebulic Myrobalan) or Ying Su Ke (Poppy Capsule) to strengthen the astringent effect.
Caution: Should not be used for acute, "excess-type" diarrhea (such as sudden food poisoning), as it may trap the pathogen inside the body.

3. Common Herb Pairs

Chun Gen Pi + Huang Bo: Chun Gen Pi (Tree of Heaven Root Bark) works synergistically with Huang Bo (Amur Cork Tree Bark) to forcefully clear damp-heat. This is ideal for damp-heat dysentery or severe vaginal discharge. Requires professional diagnosis.
Chun Gen Pi + He Zi: Chun Gen Pi provides astringent properties, while He Zi (Chebulic Myrobalan) further binds the intestines. Together, they are excellent for managing long-term, chronic diarrhea. Requires professional diagnosis.

Modern Research

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

1. Main Chemical Components

Laboratory tests have identified quassinoids, flavonoids, and terpenes in the plant. In test-tube studies, extracts have shown inhibitory effects on certain bacteria and fungi. Animal studies also suggest anti-inflammatory and anti-diarrheal properties, though human clinical trials remain limited.

2. Modern Pharmacological Focus

Current scientific research primarily focuses on its antibacterial, anti-inflammatory, and anti-diarrheal effects. Labs are particularly interested in how it might help improve models of intestinal inflammation.

3. Limitations of Modern Research

When interpreting modern studies on TCM herbs, keep these points in mind:

Lab ≠ Clinic: Results from petri dishes or animal models do not automatically translate to human success.
Extracts vs. Whole Herbs: Purified single compounds do not act the same way as traditional whole-herb water decoctions.
Inconsistent Methods: Variations in dosages and preparation methods across studies make it hard to establish a single scientific standard.
Synergy is Key: The healing power of TCM comes from the synergistic interaction of all the herb's compounds, not just one isolated chemical.

Comparing Similar Herbs

1. Common Ground: Chun Gen Pi vs. Ku Shen

Both Chun Gen Pi (Tree of Heaven Root Bark) and Ku Shen (Sophora Root) clear heat and dry dampness.
Both are used in formulas for damp-heat conditions.
Both require caution regarding dosage and are inappropriate for those with weak, cold digestive systems.

2. Core Differences

Nature and Flavor: Chun Gen Pi is cold with a bitter and astringent taste. Ku Shen is much more intensely bitter and lacks the astringent quality.
Clinical Focus: Chun Gen Pi excels at binding the intestines to stop chronic diarrhea and abnormal discharges. Ku Shen focuses heavily on killing parasites and stopping itching, making it a primary choice for skin conditions.
Application: Chun Gen Pi is primarily taken internally for digestive and lower-body damp-heat. Ku Shen is frequently used externally as a wash for skin itching and rashes, in addition to internal use.
Contraindications: While both are bad for cold digestion, Ku Shen is also strictly avoided in patients with Yin deficiency without heat.

3. Summary of Differences

In short, Chun Gen Pi is your go-to for clearing heat while stopping chronic diarrhea and discharge, whereas Ku Shen is preferred for clearing heat to stop skin itching and treat parasites. They are not interchangeable.

Classical Formulas Containing Chun Gen Pi

Gu Jing Wan

固經丸Assistant

Formula CategoryAstringent FormulasPrimary PatternYin DeficiencyPrimary FunctionEnrich Yin, clear Heat, stabilize menses, stop bleeding

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 Recipe: Herbal Porridge

Ingredients: 10g Chun Gen Pi (Tree of Heaven Root Bark), 50g rice.
Method: Wash the herb thoroughly and boil it together with the rice to make a porridge.
Usage: Suitable for individuals with mild damp-heat diarrhea.
Frequency: 2 to 3 times a week.
Note: Herbs are much stronger than everyday foods. Do not overconsume, and avoid entirely if you have a cold digestive system.

2. Decoction and Processing Differences

Raw vs. Processed: Raw Chun Gen Pi is hard, making its active ingredients difficult to extract, so it should be decocted first. The processed version, Chao Chun Gen Pi (Stir-fried Tree of Heaven Root Bark), is crispier and easier to extract.
Cooking Method: Soak the clean herbs in water for about 30 minutes. Bring to a boil over high heat, then reduce to a low simmer.
Dosage Forms: Never substitute the dosage of a water decoction directly for pills or powders.

3. Dosage and Usage Cycle

Standard traditional dosages range from 6 to 12 grams. Dietary (food-therapy) doses should be kept much lower.
Do not use long-term, as its cold nature will eventually damage your body's vital energy (Qi). Always consult a professional if you fall into a vulnerable health category.

Contraindications & Safety Warnings

1. Inappropriate Populations

Strictly Prohibited: Pregnant and nursing women, individuals allergic to the plant, and those with a Spleen/Stomach deficiency-cold constitution.
Requires Medical Supervision: Children, the elderly, and individuals with liver or kidney impairment.

2. Drug Interactions and Dietary Notes

Consult a doctor before use if you are currently taking prescription medications, especially blood thinners or blood pressure medications.
Combining this herb with other bitter, cold herbs can significantly increase gastrointestinal irritation.

3. Adverse Reactions and Overdose Risks

Overuse may cause gastrointestinal discomfort, such as stomach pain or worsened diarrhea.
Emergency Protocol: If you experience severe allergic reactions, continuous vomiting, breathing difficulties, or rapid worsening of symptoms, stop use immediately and seek emergency medical care.

Frequently Asked Questions About Chun Gen Pi

What is Chun Gen Pi? Is it the same as Chun Pi, Chu Bai Pi or Chinese toon?

The current official name is usually Chun Pi: the dried root bark or stem bark of Ailanthus altissima (tree of heaven). The pharmacopoeial name is Ailanthi Cortex; common synonyms are Chun Gen Pi and Chu Bai Pi. Most commercial material is Ailanthus. Xiang Chun (Toona sinensis) is a Meliaceae food tree whose young shoots are eaten; some regions also sell its bark as Chun Bai Pi, which is not the same official source. The Bencao Gangmu says fragrant red Toona bark enters the Blood and astringes, while pale foul Ailanthus bark enters the Qi and is more draining—they must be told apart. Toon sprouts are a vegetable, not a substitute for medicinal bark.

What are the TCM properties and traditional uses of Chun Gen Pi?

According to the Chinese Pharmacopoeia, Chun Pi is bitter, astringent and cold, enters the Large Intestine, Stomach and Liver channels, and acts to clear heat and dry dampness, astringe to stop leukorrhea, stop diarrhea and stop bleeding. It is used for red-and-white vaginal discharge, damp-heat dysentery, chronic diarrhea and dysentery, bloody stool and uterine bleeding. Bitter-cold to clear damp-heat, astringent to secure collapse, it both dries lower-burner damp-heat and binds—an astringent heat-clearing herb, not a tonic.

What is the difference between raw and bran-fried Chun Pi?

Raw bark is more bitter-cold and better to clear damp-heat when discharge or dysentery is still hot and foul. Bran-fried Chun Pi is a little less cold and is preferred to astringe diarrhea and bleeding in longer-standing cases. Neither form should bind too early while accumulation is still sitting in new dysentery. Name raw or bran-fried on the script.

What is the usual dosage of Chun Gen Pi?

The pharmacopoeial decoction dose is 6–9 g (some texts allow 6–15 g); it may also enter pills or powders. Topically use a suitable amount as a wash or paste. Large doses can cause nausea. Reduce the dose for children and a weak Spleen-Stomach. Do not scrape garden Ailanthus or Toona bark and treat it as the official drug.

What are the contraindications of Chun Gen Pi?

Use caution or avoid in Spleen-Stomach deficiency-cold; do not bind at the outset of dysentery while accumulation remains; avoid leukorrhea or flooding from Kidney Yin deficiency without damp-heat. Bitter-cold astringency further injures Yang in cold diarrhea; binding too soon traps the pathogen; drying without damp-heat only consumes Yin. Pregnancy needs a clinician. Stop if cold abdominal pain or loose stool worsens.

Can Chun Gen Pi stop discharge, diarrhea and bleeding?

Yes, when the pattern is damp-heat. Foul red-and-white leukorrhea, damp-heat or lingering dysentery with pus and blood, intestinal-wind bloody stool and Blood-heat flooding often join Phellodendron, Coptis or Sanguisorba. Thin cold discharge, fifth-watch diarrhea and Qi-failing flooding are the wrong patterns. Acute bloody stool, high fever or severe pain needs medical care, not astringency alone.

Can it kill parasites? Can you eat it like spring toon shoots?

Tradition lists roundworm and topical tinea as adjunct uses; modern intestinal parasites should follow regulated anthelmintic protocols. Toon shoots are a spring vegetable and are not the same as medicinal Ailanthus root bark: the shoots may be eaten, the bark is bitter-cold and astringent. Stir-fried toon with egg is not “taking Chun Gen Pi.” Ailanthus itself is foul-smelling and its bark is not food.

How do you choose among Chun Gen Pi, Huang Bai, Bai Tou Weng and Chi Shi Zhi?

Phellodendron is a stronger heat-drying pair for leukorrhea: Huang Bai clears lower-burner damp-heat, Chun Pi also astringes. Pulsatilla is fiercer for hot toxic dysentery at the start; add Chun Pi only when heat-damp lingers and slippage has begun. Halloysite is warm and binds collapse—opposite in temperature to this bitter-cold bark. Stage the case; do not astringe every loose stool at once.

Which herbs is Chun Gen Pi combined with? What is the usual strategy?

Damp-heat leukorrhea joins Phellodendron, Euryale and Plantago seed. Damp-heat dysentery joins Coptis, Aucklandia and Pulsatilla, adding the astringent only after accumulation has lessened. Bloody stool or flooding may join Sanguisorba, Sophora flower, tortoise plastron or white peony. Topical washes can assist tinea. A practitioner should decide whether to clear first and bind later or to clear and bind together.

How do you choose and store Chun Gen Pi?

Choose root bark or irregular boards with a rough gray-black outer surface, a yellowish-white inner face, a faint odor and a bitter taste. Bran-fried pieces are slightly yellow. Store dry. Discard moldy or worm-eaten lots. Buy the official name Chun Pi or the synonyms Chun Gen Pi / Chu Bai Pi, and ask whether the source is Ailanthus or Toona. Use regulated slices; do not peel street-tree bark for medicine.

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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.