Wind-Damp Dispelling Formulas

二朮湯 · Èr Zhú Tāng

Er Zhu Tang

A damp-drying formula using Cang Zhu and Bai Zhu for wind-damp bi.

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Last reviewed October 2026

Formula CategoryWind-Damp Dispelling Formulas

Primary PatternDampness

Primary FunctionDry dampness, dispel wind, stop pain

Primary Therapeutic PrincipleDry dampness, dispel wind, stop pain

Main HerbsAtractylodes Rhizome · White Atractylodes Rhizome · Poria / Hoelen · Tangerine Peel · Licorice Root · Fresh Ginger

Classical SourceLater bi formula

Why This Formula?

Selected for damp bi with heaviness rather than wind-cold or blood-stasis pain.

Overview

What Is Er Zhu Tang?

1. Where the Formula Comes From

Er Zhu Tang (二术汤), or Two-Atractylodes Decoction, is a classical damp-resolving formula whose lineage goes back to the Jin-Yuan period and which was formally named in the Ming-dynasty Yi Xue Zheng Zhuan by Yu Tuan. It belongs to the category of formulas that dry damp, strengthen the spleen, regulate the qi, and settle the middle, built on the pairing of Cang Zhu (Atractylodes) and Bai Zhu (White Atractylodes).

The formula targets the pattern of damp blocking the middle burner with the spleen-stomach failing to transport. Typical signs include bloating or pain in the stomach area worse after meals, a sticky mouth with little thirst, nausea, loose or pasty stools, heavy tired limbs, and a white greasy tongue coat. It is widely used for functional dyspepsia, chronic gastritis, chronic enteritis, and functional GI disorders with a damp-blocking pattern.

In the Jin-Yuan era, doctors recognized "damp" as a core mechanism behind many miscellaneous illnesses. Li Dongyuan's Pi Wei Lun set out the idea that "when damp prevails, the yang weakens" and stressed regulating the spleen-stomach to dry damp; though he never named an Er Zhu Tang, his modified Ping Wei San and evolved Shen Ling Bai Zhu San recipes, with Cang Zhu and Bai Zhu used together, laid its foundation. Zhu Danxi, in the Dan Xi Xin Fa, then refined when to use each of the two Zhu for damp-heat versus cold-damp — the key step turning a prototype into a practical formula.

2. Functional Dyspepsia

Functional dyspepsia is a common indication. Poor diet and long strain weaken the spleen-stomach and block the middle burner with damp: post-meal fullness, upper-abdominal pain or discomfort, poor appetite, nausea. Er Zhu Tang dries the damp, strengthens the spleen, and settles the middle, improving transport and easing those symptoms. In practice, after organic disease has been ruled out, patients matching the damp-blocking pattern usually get clear relief of post-meal fullness and upper-abdominal pain, and their appetite returns.

3. Chronic Gastroenteritis

Chronic gastritis and chronic enteritis of the spleen-damp type also suit it: long-term loose stools, bloating, abdominal pain, heavy limbs, thick greasy coat, some with fatigue and a sallow face (spleen deficiency). The formula dries the damp in the gut, strengthens transport, eases diarrhea and pain, and improves the fatigue and poor complexion. If there's clear heat (yellow greasy coat, foul stools), the formula must be adjusted with heat-clearing herbs.

4. Other Uses

Beyond those, it serves other damp-blocking conditions. In obesity, part of the problem is failed spleen transport with damp settling — heavy limbs, bloating, sticky stools — and the formula's drying and spleen-building helps the damp state and assists weight control. In abnormal vaginal discharge from damp pouring downward (copious, thick), it works with damp-draining, discharge-stopping herbs. And in heavy, aching joints from long time in damp surroundings, when the pattern is damp blocking the middle affecting the joints, strengthening the spleen and removing damp eases the joint discomfort.

How It Works

Herb Composition (Sovereign / Minister / Assistant / Envoy)

1. The Core Pair: Cang Zhu and Bai Zhu

The heart of the formula is the two Atractylodes. Though both are aster-family herbs, their natures differ:

Cang Zhu (Atractylodes) — warm, pungent-bitter; enters the spleen, stomach, and liver. Its core actions are drying damp, strengthening the spleen, and scattering wind-cold. Its drying is the stronger of the two — it removes spleen-stomach damp and also releases surface damp, suiting the patient with marked cold-damp and even some exterior signs.
Bai Zhu (White Atractylodes) — warm, sweet-bitter; enters the spleen and stomach. Its core actions are strengthening the spleen, building qi, and drying damp to drain water. Its spleen-building is the stronger — it tonifies the spleen-qi while transforming damp, suiting the patient with spleen deficiency and damp retention but not much spare upright qi.

One leans drying, one leans building: dry without injuring the spleen, build without trapping the damp — the formula's functional core.

2. The Supporting Herbs: Fu Ling, Chen Pi, Zhi Gan Cao

Fu Ling (Poria) — neutral, sweet-bland; enters the heart, lung, spleen, and kidney — drains damp through the urine and strengthens the spleen, backing up the two Zhu and giving the damp an exit. Chen Pi (Tangerine Peel) — warm, pungent-bitter; enters the spleen and lung — moves the qi, strengthens the spleen, and dries damp to dissolve phlegm, sorting out the qi the damp has blocked ("when qi moves, damp dissolves"). Zhi Gan Cao (Honey-fried Licorice) — neutral, sweet — harmonizes the whole, calms the dry herbs so they don't injure the spleen-stomach's fluids, and backs up Bai Zhu's qi-building.

3. How the Roles Are Assigned

Cang Zhu is the lord — its drying is the main attack on the spleen-stomach's damp excess. Bai Zhu is the minister — it backs up the spleen-building and adds qi, preventing the damp from wearing down the upright. Fu Ling and Chen Pi are the assistants — Fu Ling drains damp to help Cang Zhu, Chen Pi moves qi to help Bai Zhu. Zhi Gan Cao is the courier — it harmonizes everything so the formula dries and transforms damp while protecting the upright, attacking without over-damaging.

Symptoms Traditionally Associated

Clinical Presentation in TCM

1. The Root Problem: Damp Blocking the Middle Burner

The core pattern is "damp blocking the middle burner with the spleen-stomach failing to transport." In TCM the spleen-stomach are the "root of acquired constitution," in charge of transforming water, grain, and fluids. External damp (long time in a damp environment, rain, wading) or internal damp (poor diet — too much cold, raw, greasy food — injuring the spleen-stomach) makes the spleen-stomach fail, so fluids can't be transported and settle in the middle burner as damp. The damp then blocks the spleen-stomach's qi and its up-and-down movement, which further weakens transport and breeds more damp — a vicious cycle — and shows as both digestive and whole-body symptoms.

2. What It Does

Its action has three linked parts:

Dry the damp — the warm-dry herbs directly remove the damp stuck in the spleen-stomach, easing the sticky, heavy feeling.
Strengthen the spleen — restores the transport function, cutting off the source so damp can't re-settle.
Regulate the qi and settle the middle — frees the spleen-stomach's qi, restores its up-and-down movement, and eases the bloating, belching, and nausea the damp causes.

Attack and supplement in one formula — both expelling the pathogen and supporting the upright — so it suits the deficiency-excess-mixed damp patient.

3. Whom It's For

Its main scope is the symptoms and diseases of damp blocking the middle burner. Common symptoms:

Bloating or pain in the stomach area, worse after meals;
A sticky mouth with little thirst, sometimes nausea or vomiting;
Loose stools, even pasty, with more frequent bowel movements;
Heavy, tired limbs, especially the legs, more marked with activity;
A white greasy or thick greasy tongue coat, with a soft-slow or soft-weak pulse.

Common matching conditions: functional dyspepsia, chronic gastritis, chronic enteritis, and functional GI disorders — patients who show this damp-blocking picture can use it under a doctor's guidance.

Formula Analysis

The Mechanism in Classical Theory

1. The Two Zhu: Drying and Building in Tandem

The essence is the Cang Zhu–Bai Zhu partnership. Cang Zhu's drying attacks the settled damp directly — its warmth strips the damp clinging to the spleen-stomach lining — and also releases surface damp, easing the heavy limbs. Bai Zhu's spleen-building restores the transport so the damaged spleen-stomach can transform water and grain again, reducing damp at the source. Together: remove the damp that's already there and stop new damp from forming — treating branch and root. The example case: in a spleen-weak patient with heavy damp, Cang Zhu alone could dry too hard and injure the upright; Bai Zhu alone would clear the existing damp too slowly. The pair covers both.

2. Why the Supporting Herbs Are Chosen

Every assistant answers the same mechanism. Fu Ling's damp-draining sends the damp out through the urine — a key route, since damp "goes out with urination" — and amplifies the elimination. Chen Pi's qi-moving is needed because damp always blocks the qi, and the spleen-stomach's up-and-down movement depends on free qi; it restores that movement so the damp doesn't re-block, making the "qi moves, damp transforms" loop. Zhi Gan Cao's harmonizing keeps the drying from being too fierce and protects the fluids, letting the whole formula work smoothly.

3. Treating Branch and Root

The design is a classic "treat branch and root together." The branch — the symptoms of the damp already present (bloating, heavy limbs, thick greasy coat) — is handled fast by Cang Zhu's drying and Fu Ling's draining. The root — the spleen weakness and failed transport that breed the damp — is handled by Bai Zhu's spleen-building and Zhi Gan Cao's qi support. This avoids both mistakes: pure expelling (wasting the upright) and pure tonifying (trapping the damp), which is why the formula suits most damp-blocking patients and lasts well over centuries of use.

How This Formula Compares

Clinical Comparison Table

Compare	Er Zhu Tang	Ping Wei San	Qiang Huo Sheng Shi Tang	Yi Yi Ren Tang
Primary Function	Dry dampness, dispel wind, stop pain	Dry Damp, strengthen Spleen, move Qi	Dispel wind-damp, release exterior, stop pain	Dispel wind-damp, resolve swelling, ease bi pain
Formula Category	Wind-Damp Dispelling Formulas	Dampness-Draining Formulas	Wind-Damp Dispelling Formulas	Wind-Damp Dispelling Formulas
Typical TCM Pattern	Dampness	Dampness	Dampness	Dampness
Main Conditions	Joint Discomfort, Muscular Stiffness, Low Back Pain, Damp Constitution	Bloating, Poor Appetite, Stomach Discomfort, Diarrhea, Damp Constitution	Headache, Neck Pain, Joint Discomfort, Edema	Joint Discomfort, Muscular Stiffness, Edema
Main Herbs	Atractylodes Rhizome · White Atractylodes Rhizome · Poria / Hoelen · Tangerine Peel · Licorice Root · Fresh Ginger	Atractylodes Rhizome · Magnolia Bark · Tangerine Peel · Fresh Ginger · Jujube / Chinese Date · Honey-fried Licorice	Notopterygium Root · Pubescent Angelica Root · Ligusticum Root · Saposhnikovia Root · Vitex Fruit · Chuanxiong Rhizome · Licorice Root	Coix Seed / Job's Tears · Atractylodes Rhizome · Notopterygium Root · Pubescent Angelica Root · Saposhnikovia Root · Ephedra Herb · Cinnamon Twig · Chinese Angelica Root · Chuanxiong Rhizome · Licorice Root
Classical Source	Later bi formula	Tai Ping Hui Min He Ji Ju Fang (Song dynasty)	Li Dongyuan school / classical	Classical TCM formulary

How to tell them apart

Er Zhu Tang, Ping Wei San and Qiang Huo Sheng Shi Tang address damp. Ping Wei San dries middle damp. Qiang Huo Sheng Shi Tang dispels wind-damp. This formula dries damp with both Atractylodes for bi.

For educational reference only, based on traditional pattern differentiation — not a substitute for professional advice.

Clinical Modifications

Clinical Modifications for Er Zhu Tang

1. For Marked Damp

For a thick greasy coat, marked heavy limbs, and sticky stools: add Ze Xie and Zhu Ling to drain more damp through the urine; for marked distension, add Hou Po and Mu Xiang to move the qi and dry the damp; if wind rides the damp (aching joints, wind sensitivity), add Qiang Huo and Du Huo to scatter wind and dry damp. Watch the dry herbs — don't overdo them, or the fluids suffer; a little Shi Hu can protect the stomach's moisture.

2. For Marked Spleen Deficiency

For clear fatigue, poor appetite, loose stools, and a pale tongue: add Dang Shen and Huang Qi to build the qi; for marked bloating and belching, add Sha Ren and Bai Dou Kou to move the qi (so the tonics don't trap damp); for stomach-cold signs (cold, aching stomach eased by warmth), add Gan Jiang and Gui Zhi to warm the middle and drive out the cold-damp.

3. For Mixed Damp-Heat

For a yellow greasy coat, sticky mouth, and scanty dark urine: adjust with heat-clearing damp-drainers — Huang Qin and Huang Lian to clear the damp-heat; for foul stools, Ma Chi Xian and Bai Tou Weng to clear heat, drain damp, and stop diarrhea; if heat is mild and damp dominates, Hua Shi and Yin Chen — gentler than bitter-cold, sparing the spleen.

Modern Research

What the Science Suggests

1. What the Herbs Show Pharmacologically

Cang Zhu — atractylodin and atractylone regulate GI motility and improve digestion and absorption, with anti-inflammatory action that calms GI mucosal inflammation.
Bai Zhu — atractylodes polysaccharides and atractylenolides strengthen immunity, regulate spleen-stomach transport, and ease GI functional disturbance.
Fu Ling — poria polysaccharides and pachymic acid are diuretic (helping the body expel excess water) and regulate the gut flora and intestinal micro-environment.

2. Clinical Studies in GI Disease

Clinical work on functional dyspepsia and chronic gastroenteritis is encouraging: in several observational studies, symptom relief for post-meal fullness and upper-abdominal pain in functional dyspepsia reached over 80% with low recurrence; in chronic gastroenteritis it improves stool form, cuts diarrhea frequency, and raises quality of life. Research also finds the formula regulates GI hormones such as motilin and gastrin — closely tied to GI motility — which helps explain the improvement in functional disorders.

3. Other Directions

Beyond the gut, studies explore its role in obesity — regulating fat metabolism, reducing fat accumulation, and improving insulin resistance, suiting obese patients with metabolic disturbance; in allergic disease — modulating immunity and easing allergic reactions, with some benefit in damp-related allergic dermatitis; and its safety — confirming a low rate of adverse reactions with proper use, suiting long-term regulation.

Safety

Safety Considerations

1. Who Should Avoid It

Yin deficiency: dry mouth, hot palms and soles, scanty tongue coat — the warm-dry nature would deepen the fluid loss and worsen the symptoms.
Damp-heat with marked heat: a yellow greasy coat, foul stools, obvious scanty dark urine — used alone, the warm-dry would feed the heat; heat-clearing herbs are required.
Pregnancy — especially early pregnancy: the drying nature may affect the fetus; use only under a doctor, never self-directed.

2. While Taking It

Avoid cold-raw food (ice cream, sashimi, cold fruits) — it injures the spleen-stomach yang and adds damp. Avoid greasy food (fried food, fatty meat) — it loads the digestion and traps damp. Avoid spicy food (chili, Sichuan pepper) — it adds heat and, with any heat present, worsens things. Also avoid overwork, which drains the spleen-stomach upright and blunts the treatment.

3. Reactions and Handling

Side effects are relatively few, but misuse can cause trouble. A yin-deficiency patient who takes it wrongly may get dry mouth, dry stools, or mouth sores — stop, drink water, and take small amounts of nourishing foods (tremella, pear). Too large a dose or too long a course may bring a burning stomach or nausea — reduce or pause; if severe, see a doctor. Used properly under guidance, significant reactions are uncommon.

FAQ

Questions About Er Zhu Tang

Q1: What is Er Zhu Tang? Are Ping Wei San and Er Chen Tang the same?

Er Zhu Tang (二术汤) is a classic formula from the Wan Bing Hui Chun, centered on drying dampness, transforming phlegm, dispelling wind and unblocking the collaterals for phlegm-fluid obstructing the collaterals with pain in both arms, difficulty raising them and finger numbness. Ping Wei San dries dampness and moves the Spleen, leaning to dampness stagnating the middle burner. Er Chen Tang dries dampness and transforms phlegm, leaning to phlegm-damp cough. The three cannot be interchanged by equal weight. Write Er Zhu Tang. Use caution in yin deficiency and excess heat.

Q2: What is the composition and traditional use of Er Zhu Tang?

Classic composition: Cang Zhu, Bai Zhu, Nan Xing, Chen Pi, Fu Ling, Xiang Fu, Jiu Qin, Wei Ling Xian, Qiang Huo, Gan Cao, Ban Xia. It acts to dry dampness, transform phlegm, dispel wind and unblock the collaterals. It is used for phlegm-fluid obstructing the collaterals with pain in both arms, difficulty raising them and finger numbness, accompanied by obesity, fullness in the chest, dry mouth without desire to drink. Cang Zhu and Bai Zhu dry dampness; Nan Xing and Ban Xia transform phlegm; Chen Pi and Xiang Fu regulate qi; Fu Ling promotes urination; Wei Ling Xian and Qiang Huo dispel wind and unblock the collaterals; Jiu Qin clears damp-heat; Gan Cao harmonizes.

Q3: How do you choose raw versus prepared? Can Ping Wei San replace it?

Cang Zhu is soaked in rice-wash water and fried; Ban Xia is ginger-prepared. Ping Wei San lacks heavy wind-dispelling and collateral-unblocking; it cannot replace the formula by equal weight. Commercial products follow regulated compounding; do not self-modify.

Q4: What is the usual dosage? Can it be drunk daily as a dampness-drying tea?

Ancient use was decocted with fresh ginger. Modern use adjusts proportions; common as decoction, with dose named by a practitioner. It is not a four-season “Two Atractylodes tea.” Yin deficiency and excess heat only injure further. Phlegm-fluid obstructing the collaterals needs a practitioner to name a short course; it does not replace assessment.

Q5: What are the contraindications? Can it be used in pregnancy?

Yin deficiency, excess heat and pregnancy require practitioner assessment. Stop if dry mouth or constipation appears. Severe pain or worsening numbness need immediate medical care.

Q6: Can Er Zhu Tang dry dampness, transform phlegm, dispel wind and unblock the collaterals?

It can help pain in both arms, difficulty raising them and finger numbness from phlegm-fluid obstructing the collaterals. It dries dampness, transforms phlegm, dispels wind and unblocks the collaterals—not a specific for every arm pain or every numbness.

Q7: Can Er Zhu Tang be drunk daily as a dampness-drying, phlegm-transforming or collateral-unblocking tea?

Phlegm-fluid obstructing the collaterals may enter a short formula; yin deficiency and excess heat only injure further. “Atractylodes must dry dampness” does not replace assessment. Drying dampness, transforming phlegm, dispelling wind and unblocking the collaterals should be named by a practitioner with form and dose.

Q8: How do you choose among Er Zhu Tang, Ping Wei San, Er Chen Tang, Qiang Huo Sheng Shi Tang and Juan Bi Tang?

Er Zhu Tang dries dampness and transforms phlegm while dispelling wind and unblocking the collaterals, containing Cang Zhu, Bai Zhu, Nan Xing, Ban Xia, Wei Ling Xian, Qiang Huo and others, leaning to phlegm-fluid obstructing the collaterals with arm pain. Ping Wei San dries dampness and moves the Spleen, leaning to dampness stagnating the middle burner. Er Chen Tang dries dampness and transforms phlegm, leaning to phlegm-damp cough. Qiang Huo Sheng Shi Tang dispels wind and overcomes dampness, leaning to wind-damp in the exterior. Juan Bi Tang dispels wind and dispels dampness, leaning to painful obstruction. Phlegm-fluid arm pain favors Er Zhu Tang; dampness stagnation favors Ping Wei; phlegm cough favors Er Chen; exterior dampness favors Qiang Huo Sheng Shi; painful obstruction favors Juan Bi. They may be referenced after pattern differentiation; yin deficiency forbids large Er Zhu Tang.

Q9: How is Er Zhu Tang commonly modified? What is the representative use?

The original already contains drying dampness, transforming phlegm and unblocking the collaterals. Marked pain may increase Wei Ling Xian and Qiang Huo; copious phlegm may add Chen Pi and Ban Xia. Write Er Zhu Tang; do not replace the collateral-unblocking action with an equal weight of Ping Wei San.

Q10: How do you choose and store Er Zhu Tang?

Choose regulated Chinese patent medicines or classically compounded decoctions that list the composition. Moldy, damp, or abnormal-smelling lots are discarded. Store cool and dry. Buy “Er Zhu Tang”; do not replace drying dampness, transforming phlegm, dispelling wind and unblocking the collaterals with an equal weight of Ping Wei San or Er Chen Tang.

FAQ

General Questions

How do I choose the right formula?

TCM formulas are traditionally selected according to individual pattern differentiation rather than by symptom alone. If you're not sure which formula fits your presentation, take our AI Assessment below for a personalized starting point, then confirm with a qualified TCM practitioner.

What are concentrated herbal granules?

Concentrated herbal granules are made by decocting raw herbs, then extracting and concentrating the resulting liquid into a fine granule or powder form. This preserves the same active compounds as a traditional decoction while making the herbs far easier to store, measure, and prepare.

How should I take these products?

Dissolve the recommended amount of granules in hot water, stir until fully dissolved, and drink while warm — following the dosage and frequency advised by your TCM practitioner or as stated on the product packaging.

Are concentrated herbal granules equivalent to traditional decoctions?

Concentrated granules are produced from the same herbs and processed to retain their active compounds, so they are traditionally regarded as a convenient alternative to decoctions rather than a different remedy. Some practitioners note subtle differences in strength or absorption between the two forms, so your TCM practitioner may adjust dosage accordingly.

Are your products authentic?

Yes. HJMEDICAL sources its concentrated granules exclusively from established, reputable manufacturers such as Nong's and Hoi Tin, both long-standing names in the TCM granules industry, with GMP compliance stated directly on their packaging.

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HJMEDICAL sources its concentrated granules from established, reputable manufacturers such as Nong's and Hoi Tin, both long-standing names in the TCM granules industry. GMP compliance for these products is stated directly on their packaging.

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Can I take more than one formula at the same time?

Some formulas are traditionally combined, while others overlap or counteract each other. We recommend checking with a qualified TCM practitioner before combining formulas, especially if you are already taking other medication.

Are these products suitable during pregnancy or breastfeeding?

Some TCM formulas are not suitable during pregnancy or breastfeeding. Please consult a qualified TCM practitioner or your doctor before use if you are pregnant, trying to conceive, or nursing.

Do these products replace medical treatment?

No. These products are traditional herbal supplements intended to support wellbeing according to TCM principles — they are not a replacement for professional medical diagnosis or treatment. Please consult a qualified TCM practitioner or licensed healthcare provider before starting, stopping, or combining any treatment, especially if you have a chronic condition.

Medical Disclaimer

For general TCM education only — not medical advice. Consult a qualified TCM practitioner or licensed healthcare provider before use, especially if pregnant, nursing, on medication, or managing a chronic condition.

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