Roots and rhizomesHeat-clearingRadix Isatidis

Ban Lan Gen (Isatis Root)

Q: What is Ban Lan Gen? Are Da Qing Ye, Qing Dai and Nan Ban Lan Gen the same?

Official Ban Lan Gen (板蓝根) is the dried root of Isatis tinctoria . The pharmacopoeial name is Isatidis Radix . The leaf of the same plant is Da Qing Ye ( Isatidis Folium ): clears heat, resolves toxin, cools Blood and disperses macules. Leaf or stem-leaf processed into Qing Dai clears heat, resolves toxin, cools Blood, disperses macules, drains fire and settles fright. Nan Ban Lan Gen is the rhizome and root of Strobilanthes cusia, listed separately in the pharmacopoeia, and must not be mixed by equal weight. Write Ban Lan Gen. Use caution in Spleen-Stomach vacuity cold.

Q: What are the TCM properties and traditional uses of Ban Lan Gen?

According to the Chinese Pharmacopoeia, Ban Lan Gen is bitter and cold , enters the Heart and Stomach channels, and acts to clear heat, resolve toxin, cool Blood and benefit the throat . It is used for warm pestilence and seasonal toxin, fever with sore throat, macules from warm toxin, mumps, rotten-throat cinnabar sand, massive-head pestilence, erysipelas and abscess. Bitter-cold and resolving, it suits heat-toxin sore throat and macules from warm toxin—not vacuity without excess fire, or Spleen-Stomach vacuity cold.

Q: What is the usual dosage? Can it be drunk daily as a heat-clearing tea?

The pharmacopoeial decoction dose is 9–15 g . It is not a four-season “isatis preventive tea.” Without excess fire, cold only injures Spleen yang. Sore throat and macules need a practitioner to name a short course; it does not replace pathogen and throat assessment.

Q: How do you choose and store Ban Lan Gen?

Choose cylindrical roots, gray-yellow outside, a yellow-white cortex and yellow wood on the cut face, slightly sweet then bitter-astringent . Moldy, moth-eaten, blackened or dirty lots are discarded. Store dry against mold and moths. Buy pharmacopoeial Ban Lan Gen; do not replace clearing heat, resolving toxin, cooling Blood and benefiting the throat with isatis leaf or southern isatis root by equal weight.

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

View Herb Profile →

Last reviewed Oct 13, 2026

Quick Facts

Latin Name	Radix Isatidis
Chinese Name & Pinyin	板藍根 · Ban Lan Gen
Medicinal Part	Roots and rhizomes
The herb	Ban Lan Gen is the dried root of Isatis indigotica. Da Qing Ye is the leaf of the same plant. Qing Dai is a processed product.
Nature and channels	Bitter, cold. Enters the Heart and Stomach. Bitterness resolves toxin. Cold cools the blood and eases the throat.
Pharmacopoeia line	Clears heat and resolves toxin. Cools the blood and eases the throat. Used for seasonal toxin, fever and sore throat, warm-toxin macules, mumps, throat-bi, eroded scarlet throat, massive-head pestilence, erysipelas, and abscesses.
Pattern cues	Fever and sore throat. Mumps. Throat-bi. Erysipelas. Abscesses. Red tongue with yellow coating.
In this article	Ban Lan Gen versus Da Qing Ye, Qing Dai, and Niu Bang Zi. Heat versus no heat. Why a weak spleen should skip it. Why severe cases need a clinic. Who should skip it.

What Is Ban Lan Gen?

Ban Lan Gen (板蓝根; Bǎn Lán Gēn; Latin: Isatidis Radix; English: isatis root) is the dried root of Isatis indigotica Fort. In Chinese medicine it is a heat-clearing, toxin-resolving herb. It is bitter and cold, enters the Heart and Stomach channels, and its core actions are to clear heat and resolve toxin, and to cool the blood and ease the throat. It is not Da Qing Ye. That is the leaf of the same plant, and more clearly clears heat and cools the blood. It is not Qing Dai. Indigo is a processed product. It clears the Liver, cools the blood, and settles fright. Ban Lan Gen leans toward easing the throat and resolving warm toxin. A cold weak spleen is a contraindication. Mumps, eroded throat, and high fever need a clinic. The pharmacopoeia line is not an antiviral-drug claim, and the root is not a daily prevention tea for people with no heat.

It is used most often for three patterns:

Warm-toxin fever and sore throat — seasonal toxin
Mumps, throat-bi, eroded scarlet throat, massive-head pestilence — seek care
Erysipelas and abscesses

The usual decoction dose is 9–15 g. Bitter and cold, it is not a daily “cold isatis” drink for everyone. Bitter cold with no heat injures the spleen and stomach.

When warm toxin attacks the throat, fever, sore throat, and swollen cheeks are common. Ban Lan Gen is bitter-cold. It clears, cools, and eases the throat, which is why it appears in warm-toxin throat formulas. It drains more than it warms. Chills with no sweat, loose stools, and a white coating get worse if more cooling is added.

Ban Lan Gen is not a catch-all cold root. In wind-cold common cold or middle-cold diarrhea, using it alone can cool and trap the pathogen. Whether it belongs in a formula should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Ban Lan Gen: Materia Medica Profile

Identification & Quality Standard

Radix Isatidis

Botanical Origin

The dried root of Isatis indigotica Fort. (Brassicaceae).

Production Regions

Primarily produced in the provinces of Henan, Hebei, Anhui, Jiangsu, and northeastern China.

Quality Requirements

Superior medicinal material has straight and thick roots, firm texture, and powdery.

Macroscopic Features

Long cylindrical, 10~20~30cm long, 3~8mm diameter. Externally pale grayish-yellow, rough, longitudinal wrinkles and horizontal spots, with supporting roots; head of root is slightly enlarged; apex has one concave, surrounded by dark green remnants of petioles; relatively thick root has dense verrucous protrusions and grayish-brown petiole scars are arranged in a wheel-like shape. Firm and brittle texture; fractured surface has yellowish-white to pale brown cortex, with yellow xylem. faint odor; taste slightly sweet.

3 Sourcing and Quality Identification

Traditionally, the best quality roots come from regions like Hebei and Jiangsu, though modern quality also depends heavily on harvest time and processing.

Visual Check: A high-quality Ban Lan Gen (Isatis Root) is cylindrical with a grayish-yellow or brownish-yellow surface. It features vertical wrinkles and small, horizontal, pore-like bumps.
Texture and Color: It should feel solid. When broken, the outer layer (bark) is yellowish-white, and the inner core (wood) is distinctly yellow.
Taste and Smell: It has a very faint odor. The taste is initially slightly sweet, followed by a bitter and astringent finish.
Imposter Warning: It is sometimes confused with the root of European Isatis, which has a much paler cross-section and a slightly different smell.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Bitter; ColdHeartStomach

1. 2 Historical Records

This herb has been highly valued throughout TCM history for combating "heat-toxins":

Ming Yi Bie Lu (Miscellaneous Records of Famous Physicians): Noted its ability to clear toxicity and kill parasites.
Xin Xiu Ben Cao (Newly Revised Materia Medica): Highlighted its use for clearing skin rashes and treating epidemic heat-toxins.
Ben Cao Bian Du (Convenient Reader of Materia Medica): Emphasized its power to clear deep-seated heat in the Upper Jiao (upper body) and Stomach.

2. 3 Evolution of TCM Understanding

Over centuries, practitioners have refined their understanding of how best to use this herb:

Primary Uses: Many experts focus on its ability to clear the throat and resolve toxicity, making it a go-to for sore throats caused by "wind-heat" (like early-stage colds).
Cooling the Blood: Others emphasize its ability to cool the blood, using it for mild skin rashes erupting during early-stage heat illnesses.
Important Precaution: Because it is very cold, practitioners warn against long-term use for people with "Spleen and Stomach cold-deficiency" (those who suffer from chronic poor digestion, bloating, or cold stomachs), as it can damage the body's digestive fire. It is a targeted remedy, not a cure-all.

Core Efficacies & Traditional Applications

Traditional Functions

Clears hear, resolves toxin, cools the blood, benefits the throat. Apply to eruptions due to epidemic heat syndrome, headaches caused by chronic fever, epidemic disease characterized by swelling and redness of face, dark purple crimson tongue, scarlet fever, erysipelas, mumps, pharyngitis, swelling sores, chicken pox, measles, hepatitis, influenza, epidemic meningitis, Japanese B encephalitis, pneumonia, coma, hematemesis and non-traumatic hemorrhage, swelling throat, acute scleritis, sore and eruption.

1. 1 First Primary Action: Clearing Heat and Soothing the Throat

The primary traditional function of Ban Lan Gen (Isatis Root) is to clear warm-heat pathogens from the throat, effectively relieving redness, swelling, and pain.

Common Symptoms: It is widely used for early-stage "wind-heat" (such as the onset of a common cold) or when heat-toxins accumulate in the throat. Symptoms include a red and swollen throat, pain that worsens when swallowing, mild fever, and a dry mouth.
Common Pairings: To enhance its throat-clearing effects and prevent this bitter-cold herb from upsetting the stomach, it is frequently combined with other herbs like Jie Geng (Platycodon Root) and Gan Cao (Licorice Root).
Caution: Individuals with Spleen and Stomach cold-deficiency (e.g., those who frequently have loose stools or poor digestion) should not use this herb on their own, as it can worsen stomach discomfort.

2. 2 Second Primary Action: Clearing Heat-Toxins from the Skin

Another key function is clearing heat-toxins from the skin's surface, helping to relieve mild skin eruptions and bright red rashes caused by internal heat.

Common Symptoms: It is used during the early stages of warm-heat diseases when red spots appear on the skin, or for heat-induced rashes accompanied by mild itching or a burning sensation.
Common Pairings: It is often paired with blood-cooling herbs like Mu Dan Pi (Moutan Bark) and Chi Shao (Red Peony Root) to clear deep heat, as well as wind-dispersing herbs to help vent the pathogens out of the body.
Caution: People with a cold-deficiency constitution (those who constantly feel cold or have cold hands and feet) should avoid using it, as its cold nature can damage the body's warming energy (Yang).

3. 3 Common Single Herb Pairing: The Herb Pair

A classic and highly effective pairing is Ban Lan Gen (Isatis Root) with Jie Geng (Platycodon Root).

Synergy: Ban Lan Gen focuses on clearing heat-toxins from the throat, while Jie Geng opens the lungs, soothes the throat, and acts as a "guide" to carry the medicinal effects upward. Together, they enhance throat relief while preventing the heavy, cold nature of Ban Lan Gen from sinking too quickly into the stomach.
Usage: This pair is excellent for wind-heat-induced sore throats and hoarseness. However, it requires a practitioner to adjust the dosage based on your specific constitution.

Modern Research

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

1. 1 Key Chemical Components

Laboratory analysis shows that Ban Lan Gen (Isatis Root) contains organic acids, flavonoids, and indole derivatives, with the latter being the primary active compounds.

Lab Observations: In test-tube studies, these compounds have shown some ability to inhibit certain common pathogens.
Animal Studies: Extracts have demonstrated mild fever-reducing effects in animal models.
Human Use: Current clinical research mostly focuses on its preliminary benefits in soothing throat discomfort, though more robust human trials are needed to confirm specific efficacies.

2. 2 Modern Pharmacological Directions

Today, scientific research on this herb generally focuses on:

Isolating and purifying its active compounds.
Observing its antimicrobial potential in laboratory settings.
Exploring its potential immune-modulating effects in animal models.
Note: The exact mechanisms are still being studied, and massive human clinical data is still developing.

3. 3 Limitations of Modern Research

While modern lab work provides interesting context, it is important to view it through the proper lens:

Lab vs. Human Body: Results from a petri dish or animal model do not automatically translate to clinical success in humans.
Extracts vs. Whole Herb: Highly concentrated, isolated chemicals act very differently than the traditionally prepared whole root.
Holistic Synergy: TCM relies on the synergistic effect of the whole plant. Pinning the herb's entire value on a single chemical component misses the broader picture of how the whole herb interacts with the human body.

Comparing Similar Herbs

1. 2 Similarities with Comparable Herbs

Ban Lan Gen (Isatis Root) and Da Qing Ye (Isatis Leaf) both share the primary function of clearing warm-heat pathogens. Both are used for early-stage throat discomfort or mild skin heat-toxins, and both require caution for people with cold-deficiency body types.

2. 3 Core Differences

Nature and Texture: Both are cold and bitter, entering the Heart and Stomach meridians. However, Da Qing Ye is slightly less harsh in its bitter-coldness, and because it is a leaf, its energy is lighter and tends to float upward and outward.
Primary Focus: Ban Lan Gen directly targets the throat, making it highly effective for localized redness and pain. Da Qing Ye is much better at venting heat-toxins through the skin (treating rashes and spots), with throat-clearing as a secondary benefit.
Action Mechanism: Ban Lan Gen has a sinking, downward action, clearing heat from the upper body and stomach. Da Qing Ye has a dispersing, outward action, pushing heat-toxins out through the body's surface.
Target Symptoms: Choose Ban Lan Gen for severe throat pain, dry mouth, and a burning sensation in the stomach. Choose Da Qing Ye for skin rashes, mild fever, and hot skin.
Digestive Impact: Both can upset a weak stomach, but Ban Lan Gen is slightly harsher on the digestive system due to its stronger downward-clearing nature.

3. 4 One-Sentence Summary

Ban Lan Gen (Isatis Root) is your heavy-hitter for localized throat pain and internal heat, while Da Qing Ye (Isatis Leaf) is better for pushing heat-toxins outward to treat skin rashes and spots.

Classical Formulas Containing Ban Lan Gen

Pu Ji Xiao Du Yin

普濟消毒飲

Formula CategoryHeat-Clearing FormulasPrimary PatternWind-HeatPrimary FunctionClear heat, resolve toxin, disperse wind-heat from the head and faceRelated ConditionsSore Throat·Fever·Headache

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. 1 Home Tea or Dietary Application

Ban Lan Gen and Licorice Tea:
- Ingredients: 3g raw Ban Lan Gen (Isatis Root), 2g Gan Cao (Licorice Root).
- Method: Place both in a cup, steep with boiling water, cover, and let sit for 10 minutes.
- Best For: Early-stage wind-heat with mild sore throat and dry mouth.
- Limits: Drink a maximum of 3 times a week (1 cup per time), and do not use for more than 3 consecutive days. Not suitable for those with weak, cold stomachs or loose stools.
Ban Lan Gen and Honeysuckle Tea:
- Ingredients: 2g raw Ban Lan Gen (Isatis Root), 1g Jin Yin Hua (Honeysuckle Flower).
- Method: Mix and steep with boiling water for 5 minutes.
- Best For: Occasional mild internal heat, such as bad breath or a slightly scratchy throat during seasonal transitions.
- Limits: Drink up to 2 times a week. Do not use continuously.

2. 2 Preparation Differences

Raw vs. Processed: The raw herb (Sheng Ban Lan Gen) is stronger for clearing the throat and skin. The stir-fried version is slightly milder and less bitter-cold, making it gentler on the stomach.
Brewing: For home decoctions, raw Ban Lan Gen can be boiled directly with other herbs for about 15 minutes. It does not require special steps like pre-boiling or wrapping.
Format Swapping: Do not directly swap raw dried herbs with commercial instant granules or powders, as their concentrations and effects differ entirely. Follow package instructions or a doctor's advice.

3. 3 Dosage and Usage Cycle

Dosage: In traditional clinical prescriptions, the dosage is usually 9 to 15 grams. For home dietary use (like teas), the dose should be kept much lower, between 2 to 5 grams.
Cycle: This is a short-term remedy. Use for a maximum of 3 days. If symptoms do not improve, stop taking it and consult a doctor.
Special Populations: Children and the elderly must use reduced doses strictly under medical supervision.

Contraindications & Safety Warnings

1. 1 Not Suitable For

Cold-Deficiency Types: Anyone with a weak Spleen/Stomach, chronic loose stools, a cold abdomen, or cold hands and feet should avoid it.
Vulnerable Groups: Pregnant and nursing women must consult a doctor before use. Children and the elderly should only use it under strict professional dosage control.
Organ Health: Those with liver or kidney dysfunction should consult a physician, as the body needs these organs to metabolize the herb.
Allergies: Do not use if you are allergic to plants in the Brassicaceae (mustard) family.
Special Treatments: Individuals undergoing chemotherapy or taking immunosuppressants must consult their doctor to avoid dangerous interactions.

2. 2 Drug Interactions and Dietary Notes

Medications: Ban Lan Gen (Isatis Root) may interact with blood thinners, blood pressure medications, and diabetes drugs, potentially affecting how they work. Always consult a pharmacist or doctor if you are on prescription meds.
Diet: While there is no strict "food combining" danger, always check with a professional about mixing herbs with your specific medications to prevent adverse reactions.

3. 3 Adverse Reactions and Risks

Digestive Upset: Some people may experience mild stomach discomfort, nausea, or bloating. If this happens, reduce the dose or stop entirely.
When to Seek Help: If you experience severe allergic reactions (such as rashes, severe itching, or difficulty breathing), persistent vomiting, confusion, or if symptoms rapidly worsen, stop use immediately and go to an emergency room. Do not try to manage severe reactions at home.

Frequently Asked Questions About Ban Lan Gen

What is Ban Lan Gen? Are Da Qing Ye, Qing Dai and Nan Ban Lan Gen the same?

Official Ban Lan Gen (板蓝根) is the dried root of Isatis tinctoria. The pharmacopoeial name is Isatidis Radix. The leaf of the same plant is Da Qing Ye (Isatidis Folium): clears heat, resolves toxin, cools Blood and disperses macules. Leaf or stem-leaf processed into Qing Dai clears heat, resolves toxin, cools Blood, disperses macules, drains fire and settles fright. Nan Ban Lan Gen is the rhizome and root of Strobilanthes cusia, listed separately in the pharmacopoeia, and must not be mixed by equal weight. Write Ban Lan Gen. Use caution in Spleen-Stomach vacuity cold.

What are the TCM properties and traditional uses of Ban Lan Gen?

According to the Chinese Pharmacopoeia, Ban Lan Gen is bitter and cold, enters the Heart and Stomach channels, and acts to clear heat, resolve toxin, cool Blood and benefit the throat. It is used for warm pestilence and seasonal toxin, fever with sore throat, macules from warm toxin, mumps, rotten-throat cinnabar sand, massive-head pestilence, erysipelas and abscess. Bitter-cold and resolving, it suits heat-toxin sore throat and macules from warm toxin—not vacuity without excess fire, or Spleen-Stomach vacuity cold.

Does Ban Lan Gen need special processing? Can Da Qing Ye replace it?

Remove foreign matter, wash, soften, cut thick slices and dry. Isatis leaf leans to cooling Blood and dispersing macules; it cannot replace benefiting the throat by equal weight. Southern isatis root is a separate monograph and must not be called Ban Lan Gen. Commercial granules are not equal-weight pieces and should not be drunk long-term as a preventive tea.

What is the usual dosage? Can it be drunk daily as a heat-clearing tea?

The pharmacopoeial decoction dose is 9–15 g. It is not a four-season “isatis preventive tea.” Without excess fire, cold only injures Spleen yang. Sore throat and macules need a practitioner to name a short course; it does not replace pathogen and throat assessment.

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

Unsuitable in vacuity without excess fire, and in Spleen-Stomach vacuity cold with loose stool. Pregnancy needs a practitioner’s assessment; do not take it preventively on your own. Stop if poor appetite and diarrhea appear. High fever with clouded spirit, difficulty breathing and neck stiffness are emergencies.

Can Ban Lan Gen clear heat, resolve toxin, cool Blood and benefit the throat?

It can help sore throat from warm toxin and mumps. Massive-head pestilence with swelling of the head, face and throat may enter Pu Ji Xiao Du Yin, with Scutellaria, Coptis, burdock fruit, scrophularia and puffball. It clears heat, resolves toxin, cools Blood and benefits the throat—not a specific for every cold or every influenza.

Can Ban Lan Gen be drunk daily to prevent colds, benefit the throat or disperse macules?

Heat-toxin sore throat may enter a short formula; without heat, clearing only loosens the stool. “Isatis root must prevent influenza” does not replace vaccination and medical care. Clearing heat, resolving toxin, cooling Blood and benefiting the throat should name 9–15 g.

How do you choose among Ban Lan Gen, Da Qing Ye, Qing Dai, Jin Yin Hua and Niu Bang Zi?

Isatis root is bitter-cold: clears heat, resolves toxin, cools Blood and benefits the throat—warm-toxin sore throat and mumps. Isatis leaf is bitter-cold: clears heat, resolves toxin, cools Blood and disperses macules—stronger for macules. Indigo is salty-cold: clears heat, resolves toxin, cools Blood, disperses macules, drains fire and settles fright—small dose, often in pills and powders. Honeysuckle is sweet-cold: clears heat, resolves toxin and disperses wind-heat. Burdock fruit is acrid-bitter and cold: disperses wind-heat, resolves toxin, benefits the throat and vents rash. Benefiting the throat favors Ban Lan Gen; macules favor Da Qing Ye; high fever with clouded spirit favors Qing Dai with dose control; wind-heat favors Jin Yin Hua; sore throat with rash favors Niu Bang Zi. They may be paired; Spleen-Stomach vacuity cold forbids large Ban Lan Gen and Da Qing Ye.

Which herbs is Ban Lan Gen combined with? What are the representative formulas?

Massive-head pestilence and swollen sore throat join Scutellaria, Coptis, burdock fruit, scrophularia and puffball in Pu Ji Xiao Du Yin. Macules from warm toxin may join isatis leaf and Rehmannia after pattern differentiation. Write Ban Lan Gen 9–15 g; do not replace it with southern isatis root by equal weight.

How do you choose and store Ban Lan Gen?

Choose cylindrical roots, gray-yellow outside, a yellow-white cortex and yellow wood on the cut face, slightly sweet then bitter-astringent. Moldy, moth-eaten, blackened or dirty lots are discarded. Store dry against mold and moths. Buy pharmacopoeial Ban Lan Gen; do not replace clearing heat, resolving toxin, cooling Blood and benefiting the throat with isatis leaf or southern isatis root by equal weight.

Related Products

Nong's Ban Lan Gen Concentrated Granules

Nong's Ban Lan Gen (Isatis Root) Single Herb 5:1 Concentrated Granules $49.11

Hoi Tin Pu Ji Xiao Du Yin Pu Ji Xiao Du Ke Li Extract Granules

Hoi Tin Pu Ji Xiao Du Yin (Universal Benefit Toxin-Dispersing Beverage) 5:1 Concentrated Granules $30.50

Nong's Pu Ji Xiao Du Yin Extract Granules

Nong's Pu Ji Xiao Du Yin (Universal Benefit Toxin-Dispersing Beverage) 5:1 Concentrated Granules $65.16

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.