Zoological substancesPhlegm-resolvingMeretricis Concha / Cyclinae Concha

Ge Ke (Clam Shell)

A practical guide to Ge Ke: 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 Oct 28, 2026

Quick Facts

Latin Name	Meretricis Concha / Cyclinae Concha
Chinese Name & Pinyin	蛤殼 · Ge Ke
Medicinal Part	Zoological substances
The item	Ge Qiao is the shell of the hard clam, raw or calcined. Mu Li (oyster shell) and clam meat are not this drug.
Nature and channels	Cold, salty, bitter. Enters the Lung, Kidney, and Stomach. Cold salty bitter clears lung heat, transforms phlegm, softens hardenings, and scatters accumulations.
Pharmacopoeia line	Clears lung heat and transforms phlegm; softens hardenings and scatters accumulations. Used for heat cough with thick phlegm and chest stuffiness, and for classic phlegm-knot swellings.
Pattern cues	Thick yellow phlegm. Harsh cough. Chest stuffiness. Neck lumps. Hard knots.
In this article	Ge Qiao versus Mu Li. Clearing lung phlegm versus anchoring the liver. Why it is decocted first. Who should skip it. Home tea and soup.

What Is Ge Ke?

Ge Qiao (蛤壳; Gé Qiào; Latin: Concha Meretricis Seu Cyclinae; English: clam shell) is the shell of the common hard clam — the flat, fan-shaped shell washed up on the shore, cleaned and dried as a medicinal piece. It is cold, salty, and bitter, enters the Lung, Kidney, and Stomach channels, and its core actions are to clear lung heat and transform phlegm, and to soften hardenings and scatter accumulations. It is the coastal remedy for heat-and-phlegm coughs and classic "knots" under the skin. The usual amount is 6–15 g in a decoction. Because the shell is hard, it is usually decocted first for 15–20 minutes. The calcined powder form is taken stirred into water.

It is not Mu Li. Oyster shell is salty, astringent, and slightly cold — it anchors the liver and secures leakage, but it does not clear lung phlegm. It is not a "cough lozenge" either; the medicinal shell is processed and dosed by a practitioner. In a cold weak spleen-stomach — frequent loose stools, cold hands — or in pregnancy, using it on your own is a poor match. Coughing up blood, or a lump that keeps growing, needs a clinic first. Do not take it yourself for a long time.

It is used most often for three patterns:

Heat cough with thick yellow, sticky phlegm — phlegm-heat in the lung
Classic neck lumps, or a hard knot under the skin — qi bound with phlegm
Coughing up blood, or a lump that keeps growing — seek care

Cold, salty, and bitter, it is not a daily "lung-cooling powder" to keep taking. Coldness when there is no heat, or softening when there is no knot, chills and drains a weak body.

When heat and phlegm clog the lung, the cough turns harsh and the phlegm thick and yellow; when qi binds with phlegm, hard knots form under the skin. Ge Qiao is cold, salty, and bitter. It clears, thins, and softens, which is why it appears in Hai Ge San (Sea Clam Powder)–type formulas. It drains more than it holds. In a cold weak spleen-stomach, with no heat or knot, more makes it worse.

Ge Qiao is not a catch-all lung-cooling or knot-softening shell. In deficiency-cold, with no heat or knot, or in pregnancy, using it alone is a poor match. Whether it belongs in a formula, and at what dose, should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Ge Ke: Materia Medica Profile

Identification & Quality Standard

Meretricis Concha / Cyclinae Concha

Botanical Origin

The dried shell of Meretrix meretrix Linnaeus or Cyclina sinensis Gmelin (Veneridae). Harvest during summer and autumn, removes the flesh, clean, and dry.

Production Regions

Primarily produced in the Chinese provinces of Hainan, Jiangsu, Fujian, Guangdong.

Quality Requirements

Superior medicinal material has circular arc front edge, firm texture.

Macroscopic Features

Meretrix meretrix Linnaeus: fan-shaped or semi-spherical, edge of back is slightly triangular, front edge is circular arc, 3~10cm long, 2~8cm tall. Raised apex of shell, located at back side slightly forward. Outer shell surface is smooth, yellowish-brown, with obvious concentric lines; back often has saw-teeth or wavy brown lines. Inner shell is white, without teeth lines on the edge; some front and back shells have a slightly purple color, hinge is relatively wide; right shell has 3 main teeth and 2 front-side teeth; left shell has 3 main teeth and 1 front-side teeth. Firm texture; fractured surface has layered lines. faint odor; tasteless. Cyclina sinensis Gmelin: Sub-spherical, raised apex of shell located at the near central position of back side. Outer shell surface is pale yellow or brown-reddish, raised rib-like lines with a slight concentric arrangement. Inner shell is white or pale red, edge is often slightly purple with neat small teeth-like lines; both sides of hinge have 3 main teeth, without side teeth.

Main Regions and Quality Identification

Classic texts and trade experience favor shells from several coastal provinces, but quality still depends on species, harvest time, processing, and storage. Good raw Ge Qiao comes as whole or near-whole fan-shaped shells with clear patterns, a porcelain-white interior, and no smell; the calcined form is gray-white powder, fine, without the fishy note. The common look-alike is oyster shell — heavier, with rough scaly surfaces — easily told apart from the porcelain-white clam shell with its growth-line pattern.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Bitter, Salty; ColdLungKidneyStomach

1. Records in Classic Materia Medica

Shen Nong Ben Cao Jing: records the sea clam shell "is used for cough with qi rising, wheezing, fullness and vexation of the chest, and chest pain with alternating chills and fever."
Ming Yi Bie Lu: adds it "frees the joints, opens the nine orifices, and stops wasting thirst."
Xin Xiu Ben Cao: records it for swelling, dribbling urine, and heat binding.
Ben Cao Gang Mu: records it "clears heat and dampness, transforms phlegm fluids, disperses accumulations, and is used for women's blood-qi stabbing pain, discharge, and blood masses."
De Pei Ben Cao: notes it "clears lung heat, transforms phlegm qi, and disperses goiter-type swellings."
Zhong Hua Ben Cao: gathers the modern reading — phlegm-heat cough and classic phlegm-knot swellings.

2. How Views of Its Nature Changed

Early doctors leaned on the clearing and water-moving side — cough, wheeze, and heat; later doctors stressed the softening side — for knots under the skin; still others drew the line — the shell is cold, so a cold weak spleen-stomach must use it sparingly, and it is not for a plain deficiency-cold cough. The reading sharpened with time, keeping it from being used as a universal clearing shell.

Core Efficacies & Traditional Applications

Traditional Functions

Clears heat and resolves phlegm, softens hard masses and dissipates nodules, neutralizes acid and relieves pain.

1. Main Use 1: Clearing Lung Heat and Transforming Phlegm

(1) Traditional action: clearing phlegm-heat from the lung and easing the harsh cough it causes. (2) Typical patterns: phlegm-heat cough — thick yellow sticky phlegm, a harsh cough, chest stuffiness, a yellow greasy tongue coat, dry mouth with a bitter taste. (3) Usual pairings: Huang Qin (skullcap) and Gua Lou (snakegourd fruit) to strengthen the clearing. (4) Not for self-use: a cold weak spleen-stomach — frequent loose stools, cold hands — the cold can add to the chill.

2. Main Use 2: Softening Hardenings and Scattering Accumulations

(1) Traditional action: softening and dispersing classic knots — the neck lumps of the old literature, and hard internal knots of phlegm-and-qi origin. (2) Typical patterns: qi bound with phlegm — emotional stuffiness, a firm lump that does not hurt much. (3) Usual pairings: Chen Pi (tangerine peel) and Zhe Bei Mu (fritillary bulb) to move qi and transform phlegm. (4) Not for self-use: a knot from pure qi-blood deficiency — softening can waste the upright qi.

3. A Classic Pairing

Ge Qiao pairs with Hai Zao (seaweed): the shell clears lung phlegm and softens knots; the seaweed disperses phlegm and moves water. Together they strengthen the knot-softening for classic phlegm-and-qi lumps — a pair that belongs to a practitioner's pattern diagnosis, not self-pairing, and a cold spleen-stomach must proceed with care.

Modern Research

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

1. Main Chemical Constituents

Detected in the shell are calcium carbonate, organic matter, and trace elements (magnesium, iron, zinc) — the usual constituents of shell materials. In vitro, some constituents have shown a mild dampening of certain inflammatory mediators. In animal experiments, a tendency toward easing cough has been observed in test mice — but no human study has yet shown a direct effect on cough in people.

2. Current Research Directions

Current work centers on anti-inflammatory and phlegm-related potential: the organic matter and trace elements may take part in respiratory inflammatory responses — mostly basic experiments so far. The calcium carbonate can also help neutralize stomach acid — consistent with its traditional entry into the Stomach channel.

3. Limitations of Current Research

Lab results are not clinical efficacy — dish and animal results do not carry over automatically to people.
Extracts are not decoction pieces — a shell releases and absorbs very differently from a single extracted component.
Doses and preparations vary between studies — results are hard to unify.
One component does not define the whole herb — the shell acts as a team; calcium carbonate alone does not define it.

Comparing Similar Herbs

1. What They Share

Both soften hardenings and scatter accumulations.
Both appear in classic formulas beside phlegm-transforming and qi-moving herbs.
Both call for constitution and dose care — cold bodies may feel the chill on a long course.

2. Key Differences

Nature and flavor: Ge Qiao is cold, salty, and bitter — clearing and draining, with a strong sinking edge; Mu Li is salty, astringent, and slightly cold — sinking but with a holding, securing character, a little more even. Focus: Ge Qiao clears lung heat and transforms phlegm — respiratory phlegm-heat; Mu Li anchors the liver, calms yang, and secures — dizziness from liver yang, night sweats, seminal leakage. Tendency: Ge Qiao works on the lung and stomach, draining phlegm-heat downward; Mu Li also gathers the floating yang — a securing direction. Best fit: Ge Qiao for heat cough with thick yellow phlegm and phlegm-knot swellings; Mu Li for liver-yang dizziness, excessive sweating, and leakage-type complaints. Who should avoid: Ge Qiao is wrong for a cold weak spleen-stomach; Mu Li is wrong for the same bodies and for heat-type constipation — the astringent hold can add to it. Where you meet them: Ge Qiao in respiratory clearing formulas and folk phlegm soups; Mu Li in liver-calming and securing formulas, rarely in daily respiratory care.

3. One-Line Takeaway

In short, Ge Qiao clears lung phlegm and targets heat-type knots; Mu Li anchors the liver and secures leakage. Both can appear in knot care — but they are not stand-ins for each other.

Classical Formulas Containing Ge Ke

Classic Formula 1: Hai Ge San

Role of this herb: in Hai Ge San (Sea Clam Powder), Ge Qiao is the monarch — clearing lung heat and transforming phlegm — with Sang Bai Pi (mulberry bark) and Gua Lou Ren (snakegourd seed) beside it. The target is phlegm-heat filling the lung — harsh cough, thick yellow phlegm, chest stuffiness — and classic heat-type skin knots. Alone, one shell cannot cover the clearing, moistening, and softening at once. Traditional focus: lung phlegm-heat — cough, wheeze, chest stuffiness, thick yellow phlegm. Modern note: professional diagnosis first — never self-apply by name.

Classic Formula 2: Ge Qiao Wan

Role of this herb: in Ge Qiao Wan (Clam Shell Pill), Ge Qiao is a minister — softening and transforming phlegm — beside Hai Zao (seaweed) and Kun Bu (kelp) for dispersing, and Chen Pi (tangerine peel) for moving qi. The target is qi bound with phlegm — classic neck lumps and phlegm knots, and in the old literature, women's blood-qi stabbing pain. Traditional focus: qi-and-phlegm knots — neck lumps, phlegm kernels. Modern note: professional diagnosis first — lumps need a real examination before any herbal plan.

Formula vs. Single Herb

A formula is a coordinated team; a single herb cannot copy a full formula's effect. The doses and pairings are designed as a whole, and a herb that works in a formula does not automatically work the same way alone. Do not self-formulate from web articles — the pattern and the dose are the point.

Diet & Daily Home Use

1. Home Tea and Soup

Example 1 — Ge Qiao phlegm tea: calcined Ge Qiao 3 g, Chen Pi 2 g, Mai Dong (ophiopogon root) 2 g — steeped in boiling water 10 minutes. Fit: mild phlegm-heat in summer or early autumn — itchy throat, occasional cough, yellow coat, dry mouth; 1 cup, 1–2 times a week. Not for: a cold weak spleen-stomach, or pregnancy. Example 2 — Ge Qiao spleen soup: raw Ge Qiao 5 g (cracked), Fu Ling 10 g, Shan Yao 15 g, lean pork 50 g — simmered 1 hour, lightly seasoned. Fit: a warm-leaning spleen with mild phlegm-knot and sluggish digestion — once every two weeks as support, not a meal replacement. Not for: a plain cold spleen-stomach with no heat. Medicinal pieces are not ordinary food — no casual long-term use.

2. Decoction and Processing Differences

The raw shell clears lung phlegm better — for more obvious phlegm-heat; the calcined shell softens knots better — for lump-type care. At home, the shell is hard, so decoct it first: boil it alone 15–20 minutes, then add the other herbs or ingredients — this helps the constituents come out. Different forms cannot be converted directly — a prescription dose is not a food-use dose.

3. Dosage and How Long to Use

The classic range is 6–15 g, adjusted by pattern. Food-use amounts are small — support only, not a medicinal dose. Not for long continuous use — a single course usually stays under 3 days, and daily-style care no more than 3 times a week, so the cold does not add up. Pregnant women, children, and the elderly consult a practitioner or pharmacist first.

Contraindications & Safety Warnings

1. Who Should Avoid It

A cold weak spleen-stomach — frequent loose stools — the cold can add to the chill; pregnancy and nursing — not enough safety evidence, consult first; children and the elderly — weaker digestion, guidance only; liver or kidney impairment — be cautious; allergy to shellfish or seafood — avoid; people on anticoagulants or other medicines — consult a doctor or pharmacist first.

2. Interactions and Diet Notes

Ge Qiao may interact mildly with anticoagulants; its cold nature can partly offset warming medicines, so adjust the dose with professional help. No blanket "food clash" with ordinary foods is established, but herbs can interact with specific medicines — anyone on medication should check first.

3. Side Effects and Overuse

Misuse can bring stomach upset or nausea — more so in a cold spleen-stomach; overuse can cause diarrhea or belly pain from the cold. Stop and seek care at once for marked discomfort, an allergic reaction, persistent vomiting, trouble breathing, confusion, or a rapid worsening of symptoms.

Frequently Asked Questions About Ge Ke

What is Geqiao? Is it the same as Muli or Walengzi?

Geqiao is the shell of Meretrix meretrix or Cyclina sinensis, Latin name Meretricis Concha or Cyclinae Concha. It is a common Chinese medicine centered on clearing heat and transforming phlegm, softening hardness and dissipating binds, and neutralizing acid and relieving pain. Muli calms the liver and subdues yang while softening hardness. Walengzi disperses phlegm and resolves stasis while softening hardness. They cannot be used interchangeably in equal amounts. Prescribe as Geqiao. Caution in spleen-stomach deficiency cold.

What are the composition and effects of Geqiao?

Pharmacopoeial name Geqiao, Latin Meretrix meretrix Linnaeus or Cyclina sinensis Gmelin. Bitter and salty in taste, cold in nature, enters the Lung, Kidney and Stomach meridians. Functions to clear heat and transform phlegm, soften hardness and dissipate binds, and neutralize acid and relieve pain. Used for phlegm-fire cough, chest and hypochondriac pain, blood-streaked phlegm, scrofula and goiter, and stomach pain with acid regurgitation; externally for eczema and burns. Clears heat and softens hardness.

How to choose between raw and processed? Can Muli replace it?

Shell is used raw or calcined. Muli emphasizes subduing yang rather than strongly transforming phlegm, and cannot replace it in equal amounts. Commercial products are standardized; do not adjust arbitrarily.

What is the dosage of Geqiao? Can it be used daily as a phlegm-transforming tea?

Decoction, 6-15g, decocted first. Modern use requires physician-determined dosage. It is not a year-round "Geqiao tea." Spleen-stomach deficiency cold will be further injured by prolonged use. Cough requires short-term, physician-determined dosage and cannot replace evaluation.

What are the contraindications of Geqiao? Can pregnant women use it?

Not suitable for spleen-stomach deficiency cold. Pregnant women require physician evaluation. Stop if loose stools or abdominal pain occur. Seek immediate medical care for severe cough or high fever.

Can Geqiao clear heat, transform phlegm, and soften hardness?

It can assist phlegm-fire cough, chest and hypochondriac pain, blood-streaked phlegm, scrofula and goiter, and stomach pain with acid regurgitation; externally for eczema and burns. It clears heat and transforms phlegm, softens hardness and dissipates binds, and neutralizes acid and relieves pain, but is not a specific remedy for all cough or all stomach pain.

Can Geqiao be taken daily as a phlegm-transforming or hardness-softening tea?

Phlegm-fire cough can be used short-term in formulas; spleen-stomach deficiency cold will be further injured. The idea that "Geqiao must transform phlegm" cannot replace evaluation. Clearing heat and transforming phlegm requires physician-determined formulation and dosage.

How to choose between Geqiao, Muli, Walengzi, Haigeqiao, and Zhebeimu?

Geqiao clears heat and softens hardness while neutralizing acid, suited to phlegm-fire. Muli calms the liver and subdues yang. Walengzi disperses phlegm and softens hardness. Haigeqiao clears heat and softens hardness. Zhebeimu clears heat and transforms phlegm while dissipating binds. Choose Geqiao for transforming phlegm; Muli for subduing yang; Walengzi for dispersing phlegm; Haigeqiao for softening hardness; Zhebeimu for dissipating binds. Pattern differentiation applies, but large doses of Geqiao are contraindicated in spleen-stomach deficiency cold.

How is Geqiao commonly modified? What is a representative usage?

Modifications depend on the pattern. Add Zhebeimu for cough; add Walengzi for stomach pain. Specify Geqiao; do not substitute Muli in equal amounts for transforming phlegm.

How to select and store Geqiao?

Choose regular Chinese medicinal materials with intact shells. Discard if moldy, damp, or abnormal in odor. Store in a dry place. Purchase "Geqiao"; do not substitute Muli or Walengzi in equal amounts for clearing heat, softening hardness, and neutralizing acid.

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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.