What patterns does Qing Fen address?

Qing Fen addresses these TCM patterns of disharmony: Damp-Heat, Toxic Heat Generating Sores, Water Accumulation from Excess.

What conditions is Qing Fen used for?

Qing Fen is commonly used for: Scabies, Fungal Infection, Eczema, Chronic Ulcers, Syphilis, Acne, Impetigo, Edema, Neurodermatitis. A TCM practitioner would consider this herb when these conditions arise from the specific patterns it addresses.

Ingredient Processed / Derived product (加工品 jiā gōng pǐn)

Qing Fen

Q: What are the TCM actions of Qing Fen?

The TCM actions of Qing Fen include: Attacks Toxins and Kills Parasites, Relieves Itching, Removes Putridity and Promotes Tissue Regeneration, Absorbs Dampness and Heals Sores, Drastically Purges and Expels Water Accumulation, Promotes Bowel Movement.

Calomel · 轻粉

Hg₂Cl₂ (Mercurous chloride) · Calomelas

Also known as: Hg粉, 汞粉 (Gǒng Fěn), 腻粉 (Nì Fěn), 水银粉 (Shuǐ Yín Fěn), 银粉 (Yín Fěn), 峭粉 (Qiào Fěn), Light Powder, Mercurous Chloride

Images shown are for educational purposes only

Qīng Fěn (Calomel) is a mercury-based mineral substance used primarily as a topical medicine in Chinese medicine for stubborn skin conditions such as scabies, ringworm, chronic sores, and syphilitic lesions. It has powerful antimicrobial and antiparasitic properties but is highly toxic, so its use requires strict professional supervision and it should never be self-administered. In rare cases it was historically taken internally to treat severe edema, but this practice carries serious risks of mercury poisoning.

Category Substances for external application (外用药)

Therapeutic focus Skin Health Skin and Wound Care Parasitic skin infections Chronic Ulcer Care

TCM Properties

Temperature

Cold

Taste

Acrid / Pungent (辛 xīn)

Channels entered

Liver, Kidneys, Large Intestine

Parts used

Processed / Derived product (加工品 jiā gōng pǐn)

Educational content • Consult qualified TCM practitioners for diagnosis and treatment

What This Ingredient Does

Every ingredient has a specific set of actions — here's what Qing Fen does in the body, explained in both everyday and TCM terms

Therapeutic focus

In practical terms, Qing Fen is primarily used to support these areas of health:

Skin Health Skin and Wound Care Parasitic skin infections Chronic Ulcer Care

TCM Actions

In TCM terminology, these are the specific therapeutic actions that Qing Fen performs to restore balance in the body:

Attacks Toxins and Kills Parasites Relieves Itching Removes Putridity and Promotes Tissue Regeneration Absorbs Dampness and Heals Sores Drastically Purges and Expels Water Accumulation Promotes Bowel Movement

How these actions work

'Kills parasites and counteracts toxins' refers to Qīng Fěn's ability to eliminate skin parasites (such as scabies mites) and neutralize toxic pathogens on the body's surface. This is its primary and most important action, used topically for conditions like scabies, ringworm, and syphilitic sores. The herb's cold, acrid nature drives out toxic Heat while its mercury-based composition provides strong antimicrobial and antiparasitic effects.

'Relieves itching' means this substance stops persistent skin itching, particularly the kind caused by parasitic or fungal infections and Damp-Heat skin conditions. It is especially useful for stubborn, weeping, itchy rashes that have not responded to milder treatments.

'Removes putridity and promotes tissue regeneration' describes Qīng Fěn's role in external wound care. When mixed into ointments, it helps clear away dead, rotting tissue from chronic ulcers and sores, allowing healthy new flesh to grow in. This is the principle behind its inclusion in the famous wound-healing ointment Shēng Jī Yù Hóng Gāo.

'Expels retained water and unblocks the bowels' refers to the internal use of Qīng Fěn (used with extreme caution) to promote both urination and bowel movements in cases of severe fluid accumulation (edema, ascites) with constipation. This is a drastic action reserved for robust patients with excess-type conditions only, as the substance is highly toxic when taken internally.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony. Qing Fen is used to help correct these specific patterns.

Why Qing Fen addresses this pattern

When Damp-Heat and toxic pathogens lodge in the skin and flesh, they produce weeping, itchy, infected skin lesions such as scabies, eczema, and fungal infections. Qīng Fěn's cold nature clears the Heat component, while its acrid taste disperses the stagnant Dampness and toxins. Its strong toxin-counteracting and parasite-killing actions directly target the pathogenic factors responsible for this pattern. Topically applied, it dries Dampness, eliminates parasites, and relieves the intense itching characteristic of Damp-Heat skin conditions.

A practitioner would look for one or more of these signs

Scabies

Intensely itchy, blistering rash that worsens at night

Eczema

Weeping, crusted skin lesions with persistent itching

Fungal Infection

Ringworm and tinea with scaling and itching

Why Qing Fen addresses this pattern

When toxic Heat accumulates and festers, it causes deep ulcers, abscesses, and chronic non-healing sores with purulent discharge and decaying tissue. Qīng Fěn's cold, acrid properties clear the toxic Heat and disperse the stagnation. Its specific action of removing putridity and promoting tissue regeneration makes it especially suited for the late stages of sores where dead tissue must be cleared to allow healing. Combined with blood-moving herbs in ointment form, it resolves the stagnation underlying chronic wound non-healing.

A practitioner would look for one or more of these signs

Chronic Ulcers

Non-healing ulcers with purulent discharge and necrotic tissue

Acute Breast Abscesses

Suppurating sores that have ruptured but fail to close

Bedsore

Pressure ulcers with tissue breakdown

Why Qing Fen addresses this pattern

When water-fluid pathology accumulates in the body due to excess conditions (not deficiency), it causes severe generalized edema, abdominal distension, and obstruction of both urination and bowel movements. Qīng Fěn's acrid taste opens and moves, while its cold nature clears the concurrent Heat. Taken internally (with extreme caution), it powerfully drives water downward through both the intestines and urinary tract, acting as a harsh purgative and diuretic. This pattern must be a true excess condition in a robust patient, as the substance's toxicity makes it strictly contraindicated in weak or deficient patients.

A practitioner would look for one or more of these signs

Edema

Severe generalized water retention with firm, distended abdomen

Constipation

Complete obstruction of bowel movements accompanying fluid accumulation

Ascites

Abdominal fluid collection with urinary difficulty (excess type only)

Commonly Used For

These are conditions where Qing Fen is frequently used — but only when they arise from the specific patterns it addresses, not in all cases

Arises from: Damp-Heat

TCM Interpretation

In TCM, scabies is understood as an invasion of 'insect toxin' (虫毒) combined with Damp-Heat that lodges between the skin and flesh. The mites represent a form of parasitic toxin, while the intense itching that worsens at night (a Yin time) and the characteristic blistering, weeping lesions point to both Heat toxin and Dampness. The condition spreads because the toxic Dampness flows through the skin layer, and the scratching further disperses the toxin to new areas.

Why Qing Fen Helps

Qīng Fěn is one of the strongest parasite-killing substances in the Chinese materia medica. Its cold nature clears the Heat component of the infestation, while its acrid quality disperses the stagnant toxin lodged in the skin. Applied topically (typically mixed with oils or combined with other antiparasitic herbs like sulfur and Wú Zhū Yú), it directly kills the mites causing the condition and simultaneously dries the weeping Dampness and stops the intense itching. Classical formulas like Shén Jié Sǎn combine Qīng Fěn with sulfur and other substances specifically for this purpose.

Arises from: Toxic Heat Generating Sores

TCM Interpretation

Chronic non-healing skin ulcers are seen in TCM as a condition where toxic Heat and Blood stasis have become entrenched in the local tissue. The original cause may have been trauma, infection, or systemic Heat toxin, but over time the pathology becomes self-perpetuating: dead tissue accumulates, blocking the flow of fresh Qi and Blood needed for healing. The local stagnation generates more Heat and toxin, creating a vicious cycle. The key treatment principle is to clear the rotten tissue, resolve toxin, and invigorate Blood flow so new, healthy flesh can grow.

Why Qing Fen Helps

Qīng Fěn addresses chronic ulcers through its specific action of removing putridity and promoting tissue regeneration (祛腐生肌). In its most famous application, the ointment Shēng Jī Yù Hóng Gāo (from the Wài Kē Zhèng Zōng), Qīng Fěn works alongside Dāng Guī (which invigorates Blood), Xuè Jié (which resolves stasis), and Zǐ Cǎo (which cools Blood) to clear dead tissue, counteract local toxin, and create conditions for new flesh to form. Its antimicrobial properties help prevent reinfection of the wound bed while healing progresses.

Also commonly used for

Fungal Infection

Used externally for ringworm, tinea, and other dermatomycoses

Eczema

Applied to weeping, itchy eczematous lesions to dry Dampness and relieve itching

Syphilis

Historically a key external treatment for syphilitic sores (杨梅疮)

Acne

Applied topically for redness and pustules of the nose (酒皶鼻)

Impetigo

Used externally for infectious skin sores with yellow crusting

Edema

Rarely used internally for severe excess-type edema with constipation

Neurodermatitis

Applied in ointment preparations for chronic itchy, thickened skin patches

Ingredient Properties

Every ingredient has an inherent temperature, taste, and affinity for specific channels — these properties determine how it interacts with the body

Temperature

Cold

Taste

Acrid / Pungent (辛 xīn)

Channels Entered

Liver Kidneys Large Intestine

Parts Used

Processed / Derived product (加工品 jiā gōng pǐn)

Dosage & Preparation

These are general dosage guidelines for Qing Fen — always follow your practitioner's recommendation, as dosages vary based on the formula and your individual condition

Standard dosage

0.1–0.2g (internal use in pills or capsules only; never decocted)

Maximum dosage

Do not exceed 0.2g internally per dose, and do not exceed two doses per day. Strictly short-term use only. This substance is toxic and cumulative.

Dosage notes

Internal use: 0.1–0.2g per dose, taken in pill or capsule form only. It must never be decocted in water, as boiling decomposes mercurous chloride into highly toxic mercuric chloride and metallic mercury. After each internal dose, the mouth must be rinsed thoroughly to prevent mercury-induced oral ulceration, gum damage, and tooth loosening. Internal use should only be for genuine excess-type conditions (severe oedema with urinary obstruction, acute phlegm congestion) and must be strictly short-term. External use: appropriate amount, ground into fine powder and applied directly to affected areas, or mixed into ointments and pastes with carriers such as lard, beeswax, or oils. Do not apply over large skin areas or for prolonged periods, as systemic mercury absorption occurs through the skin.

Preparation

Must NEVER be decocted. Boiling Qing Fen in water causes decomposition into highly toxic mercuric chloride and metallic mercury. For internal use, it is ground into fine powder and taken only in pill or capsule form, in tiny doses. After ingestion, the mouth must be rinsed immediately and thoroughly to prevent mercury-induced damage to the gums, teeth, and oral mucosa. For external use, it is ground into fine powder and either dusted directly onto the affected area, or mixed into ointments and pastes with oil, lard, or beeswax as a carrier. Must be stored in sealed, opaque containers away from light, as light exposure causes dangerous decomposition.

Common Ingredient Pairs

These ingredients are traditionally combined with Qing Fen for enhanced therapeutic effect

Dang Gui Qīng Fěn 12g : Dāng Guī 60g (as in Shēng Jī Yù Hóng Gāo)

Qīng Fěn clears toxin and removes putridity from wound surfaces while Dāng Guī invigorates Blood circulation and nourishes new tissue growth. Together they address both the toxic obstruction and the Blood stasis underlying chronic non-healing sores, enabling the removal of dead tissue and the regeneration of healthy flesh.

When to use: Chronic ulcers, suppurating sores, and wounds that have ruptured but fail to heal, especially when there is necrotic tissue with poor local blood supply. This is the core pairing in the ointment Shēng Jī Yù Hóng Gāo.

Liu Huang Equal parts or adjusted based on whether Heat or Dampness predominates

Both substances powerfully kill parasites and treat skin infections, but through complementary mechanisms. Qīng Fěn is cold and clears Heat toxin, while Liú Huáng (Sulfur) is warm and dries Dampness. Together they address both the Heat and Dampness components of parasitic skin infestations more completely than either one alone.

When to use: Scabies, ringworm, and stubborn fungal skin infections with both weeping (Dampness) and redness/inflammation (Heat) components. Used in topical preparations.

Wa Leng Zi Equal parts ground into powder and mixed with oil for topical application

Qīng Fěn counteracts toxin and kills parasites with its cold nature, while Dà Fēng Zǐ (Chaulmoogra seed) dispels Wind, dries Dampness, and kills parasites with its hot, acrid nature. The combination creates a broader-spectrum antiparasitic and antifungal preparation that addresses Wind, Dampness, Heat, and toxin simultaneously.

When to use: Syphilitic sores (杨梅疮), tinea, severe scabies, and other stubborn parasitic or infectious skin conditions. Applied topically as a paste.

Gan Sui As in Zhōu Chē Wán: Qīng Fěn 1 qián (very small dose) with Gān Suì 1 liǎng

Both substances powerfully expel water from the body, but through different pathways. Gān Suì is a drastic hydragogue that purges water through the intestines by attacking fluid accumulation in the channels and interspaces. Qīng Fěn promotes water elimination through both bowels and urinary tract. Together they create an extremely powerful water-expelling combination.

When to use: Severe excess-type edema or ascites with constipation and urinary difficulty in robust patients only. This is the core mechanism of Zhōu Chē Wán. Strictly contraindicated in weak or deficient patients.

Key Formulas

These well-known formulas feature Qing Fen in a prominent role

Sheng Ji Yu Hong Gao 生肌玉紅膏 Deputy

This famous wound-healing ointment from Chén Shí Gōng's Wài Kē Zhèng Zōng is the most iconic showcase of Qīng Fěn's tissue-regenerating and toxin-clearing properties. Qīng Fěn serves as deputy alongside Dāng Guī (King), providing the formula's crucial ability to clear putridity, counteract wound toxin, and promote the growth of new flesh in chronic ulcers and post-surgical wounds.

Zhou Che Wan 舟車丸 Assistant

This drastic water-expelling formula from Zhū Dān Xī's Dān Xī Xīn Fǎ demonstrates Qīng Fěn's internal action of expelling retained water and unblocking the bowels. As an assistant, Qīng Fěn reinforces the hydragogue actions of the formula's main ingredients (Gān Suì, Dà Jǐ, Yuán Huā) by promoting elimination through both urinary and intestinal pathways, treating severe excess-type edema and ascites.

Comparable Ingredients

These ingredients have overlapping uses — here's how to tell them apart

Qing Fen vs Xiong Huang

Both are toxic mineral substances used topically to kill parasites and counteract toxins in skin conditions. However, Xióng Huáng (Realgar, arsenic sulfide) is warm and acrid, better suited for conditions dominated by Cold-Dampness, and also enters the Liver channel to calm Wind and treat convulsions. Qīng Fěn is cold, making it more appropriate when Heat toxin predominates. Qīng Fěn also has the unique internal action of expelling retained water, which Xióng Huáng does not share.

Qing Fen vs Liu Huang

Both kill parasites and treat scabies and ringworm topically. Liú Huáng (Sulfur) is hot and primarily dries Dampness, making it best for Cold-Damp parasitic conditions. Qīng Fěn is cold and clears Heat toxin, making it preferable when the skin condition has more redness, inflammation, and Heat signs. They are frequently combined to cover both aspects. Liú Huáng also has internal warming actions (tonifying Kidney Fire) that Qīng Fěn completely lacks.

Qing Fen vs Qing Fen

Both are mercury-derived substances used topically for sores and ulcers. Hóng Fěn (Hydrargyri Oxydum Rubrum, red mercuric oxide) is more potent at removing putridity and is used for heavily necrotic, deeply infected sores. Qīng Fěn (mercurous chloride) is milder and better suited for conditions where some tissue regeneration has begun or where parasite-killing and itch-relief are the primary goals. Hóng Fěn is exclusively external, while Qīng Fěn was historically also used internally (with great caution).

Common Substitutes & Adulterants

Related species and common adulterations to be aware of when sourcing Qing Fen

Qing Fen must be carefully distinguished from related mercury and mineral preparations with different toxicity profiles: 1. Mercuric chloride (HgCl2, also called 'corrosive sublimate' or Sheng Yao/升药) is far more toxic than Qing Fen and must never be confused with it. It is a divalent mercury salt with powerful corrosive properties. 2. Zhu Sha (朱砂, Cinnabar, mercuric sulfide HgS) is another mercury-containing TCM substance but has very different properties and much lower solubility. It should not be substituted for Qing Fen or vice versa. 3. Qian Fen (铅粉, lead carbonate/white lead) can resemble Qing Fen in appearance as a white powder, but is a completely different toxic substance (lead-based). The names sound similar in Chinese and confusion is possible. 4. Poor-quality Qing Fen that has been exposed to light may contain significant amounts of decomposition products (mercuric chloride, metallic mercury), making it far more dangerous than properly stored product. Always check for darkening or yellowing as signs of degradation.

Educational content — always consult a qualified healthcare provider or TCM practitioner before using any ingredient.

Toxicity Classification

Classical Chinese pharmacopoeia toxicity rating for Qing Fen

Toxic

Qing Fen (calomel, Hg2Cl2) is classified as toxic in the Chinese Pharmacopoeia. The toxic component is mercury. While mercurous chloride itself is poorly soluble and has limited intestinal absorption, it can decompose in the gut in the presence of alkali and bile salts into far more dangerous divalent mercuric ions (Hg2+) and metallic mercury vapour, both of which are highly toxic. Acute poisoning symptoms include a metallic taste in the mouth, burning sensation in the oral mucosa, severe nausea, vomiting, abdominal pain, bloody diarrhea, circulatory collapse, and acute necrotic kidney damage (tubular necrosis) that may lead to anuria, uremia, and death. Chronic poisoning (hydrargyrism) from cumulative exposure presents with: oral changes (inflamed, bleeding gums, loosening and loss of teeth, a characteristic dark mercury line on the gum margin, oral ulceration, excessive salivation); gastrointestinal disturbance; and neuropsychiatric symptoms including tremors, personality changes, irritability, insomnia, numbness of extremities (acrodynia), and cognitive decline. Liver and kidney function impairment also develops. Animal studies show the LD50 of calomel suspension is 410 mg/kg in mice and 1740 mg/kg in rats by oral gavage. Toxicity targets the kidneys most severely (tubular swelling, fatty degeneration, necrosis), with damage also to the heart, liver, and ovaries. Exposure to light causes Qing Fen to decompose into mercuric chloride and metallic mercury, both far more toxic. The substance must therefore be stored in sealed, light-proof containers. It must never be decocted in water (boiling with water accelerates decomposition into toxic forms). Internal use is limited to tiny doses (0.1-0.2g) in pill or capsule form only, for very short duration, and the mouth must be rinsed thoroughly after each dose to prevent oral tissue damage. External use should also be limited in area and duration.

Contraindications

Situations where Qing Fen should not be used or requires extra caution

Avoid

Pregnancy. Mercury in Qing Fen can cross the placenta and cause serious harm to the developing fetus, including teratogenic and neurotoxic effects.

Avoid

Kidney disease or nephritis-related edema. As a mercury compound, Qing Fen is directly nephrotoxic and can cause necrosis of renal tubular epithelium, making it extremely dangerous in patients with pre-existing kidney impairment.

Avoid

Liver disease or hepatic insufficiency. Mercury accumulates in the liver and can worsen hepatic damage. Edema or ascites caused by liver disease should not be treated with Qing Fen.

Avoid

Constitutionally weak or deficient patients (Qi deficiency, Blood deficiency, Spleen-Stomach weakness). Qing Fen is a harsh, attacking substance only appropriate for excess-type conditions in patients with sufficient constitutional strength.

Avoid

Children with chronic or slow-onset convulsions (man jing / 慢惊), or children with Spleen and Stomach deficiency. The classical text Ben Cao Yan Yi specifically warns that Qing Fen should not be used for children whose underlying condition is deficiency, as it will further deplete the body.

Avoid

Prolonged or repeated internal use. Even at low doses, cumulative mercury exposure leads to chronic mercury poisoning (hydrargyrism) affecting the nervous system, kidneys, and oral tissues. Internal use must be strictly short-term.

Avoid

Constipation due to Blood deficiency and dryness (rather than excess Heat or stagnation). The Ben Cao Jing Shu warns that bowel obstruction from Blood deficiency failing to moisten the intestines is not an appropriate indication.

Avoid

Syphilitic sores (yang mei chuang) occurring in constitutionally weak, Qi-deficient, or chronically ill patients. While Qing Fen was historically used for syphilis, it should not be used if the patient's overall condition is depleted.

Caution

Extended external application over large areas of skin or over broken/ulcerated skin. Mercury can be absorbed systemically through damaged skin, leading to toxicity even from topical use.

Caution

Sensitive skin prone to contact dermatitis. External application may trigger toxic epidermal necrolysis-like reactions with diffuse skin redness, swelling, and blistering.

Caution

Concurrent use with other mercury-containing substances (e.g. Zhu Sha/Cinnabar, other dan preparations). Combined use increases the total mercury burden and risk of toxicity.

Special Populations

Important considerations for pregnancy, breastfeeding, and pediatric use

Pregnancy

Absolutely contraindicated during pregnancy. Mercury in Qing Fen can cross the placental barrier and accumulate in fetal tissues, causing neurodevelopmental damage to the unborn child. Mercurous chloride has demonstrated ovarian toxicity in animal studies (follicular destruction in mice), and mercury exposure during pregnancy is associated with teratogenic effects. Both internal ingestion and external application carry risk, as mercury is absorbed systemically through both routes. There is no safe dose during pregnancy.

Breastfeeding

Contraindicated during breastfeeding. Mercury is excreted in breast milk and can be transferred to the nursing infant. Infants are particularly vulnerable to mercury toxicity due to their immature detoxification systems, low body weight, and developing nervous system. Even topical application by the mother poses a risk, as mercury absorbed through the skin enters the systemic circulation and can appear in breast milk. Historical reports of acrodynia ('pink disease') in infants and children exposed to calomel highlight the extreme vulnerability of the young to mercury poisoning.

Children

Generally contraindicated for internal use in children. Classical sources including the Ben Cao Yan Yi and Chen Wenzhong specifically warn that Qing Fen damages Heart Qi in children and can cause devastating harm to infants. The Ben Cao Gang Mu records that newborns and infants should especially avoid this substance. If used in children at all, it was historically restricted to topical application for skin conditions in children with robust constitutions, in small amounts and for brief duration only. Historical cases of 'pink disease' (acrodynia) in children exposed to calomel in teething powders resulted in hundreds of deaths in the mid-20th century, underscoring the extreme danger of mercury exposure in pediatric populations. No internal use in children is acceptable by modern standards.

Drug Interactions

If you are taking pharmaceutical medications, be aware of these potential interactions with Qing Fen

Mercury-containing drugs or supplements: Concurrent use with any other source of mercury (including Zhu Sha/Cinnabar, other mercury-containing TCM patent medicines, or environmental mercury exposure) increases total mercury body burden and risk of toxicity. Such combinations must be avoided.

Nephrotoxic drugs: Mercury from Qing Fen primarily damages the kidneys. Concurrent use with other nephrotoxic agents (aminoglycoside antibiotics, NSAIDs, cisplatin, cyclosporine, ACE inhibitors) could compound renal damage.

Selenium-containing supplements: Selenium can form insoluble mercury-selenium complexes and may alter mercury distribution in the body. The clinical significance is complex and unpredictable.

Chelating agents: DMPS (dimercaptopropane sulfonate) and DMSA (succimer) are used to treat mercury poisoning by binding mercury for urinary excretion. If a patient has been exposed to Qing Fen, these agents may be needed as antidotes, but their concurrent deliberate use with Qing Fen would be contradictory.

Salt-containing solutions or saline: Sodium chloride in the gut environment can promote conversion of mercurous chloride to more toxic mercuric chloride. Classical texts warn against using physiological saline for gastric lavage in cases of mercury poisoning for this reason.

Dietary Advice

Foods and dietary considerations when taking Qing Fen

When taking Qing Fen internally (under strict practitioner supervision only): avoid salty foods, as excess sodium chloride may promote conversion of mercurous chloride to more toxic mercuric forms in the gut. Avoid acidic foods and vinegar for the same reason. Consuming protein-rich foods such as eggs and milk before or after dosing may provide some protective effect, as proteins can bind mercury in the gut and reduce absorption. Classical antidote measures for mercury poisoning include egg whites and milk. Avoid alcohol, which may increase intestinal absorption of mercury.

Botanical Description

Physical characteristics and morphology of the Qing Fen source source material

Qing Fen (轻粉) is not a botanical substance but a mineral/chemical preparation. It is calomel, or mercurous chloride (Hg₂Cl₂), produced by an alchemical sublimation process. The traditional manufacturing method involves combining liquid mercury (水银), chalcanthite or alum (胆矾/白矾), and common salt (食盐) with water into a paste, mixing this with red earth, forming it into lumps, and then heating these in a flat-bottomed iron pan covered by a porcelain bowl sealed with clay. After approximately 10 hours of charcoal firing, delicate snow-white crystalline flakes condense on the inner surface of the porcelain bowl.

The resulting product appears as flaky or snowflake-like white crystals with a silvery lustre, extremely light in weight and easily crumbled into fine white powder when rubbed between the fingers. It is odourless with a faint taste. Calomel is insoluble in water and acids. When placed on iron and heated, it gradually turns yellow before volatilizing completely as a blue-green smoke, leaving no residue. It turns black when exposed to ammonia. Critically, prolonged exposure to light causes the crystals to darken as the compound decomposes into highly toxic mercuric chloride (HgCl₂) and metallic mercury, so it must be stored away from light.

Although a rare natural mineral form exists called horn mercury ore (角汞矿), the medicinal product is almost always artificially prepared through this sublimation process. The dried product must contain no less than 99.6% Hg₂Cl₂.

Sourcing & Harvesting

Where Qing Fen is sourced, when it's harvested or collected, and how to assess quality

Harvesting season

Not applicable. Qing Fen is an artificially prepared chemical product (mercurous chloride sublimed from mercury, alum/chalcanthite, and salt), not a harvested natural substance. It can be manufactured year-round.

Primary growing regions

Qing Fen is an artificially prepared chemical substance (mercurous chloride), not a naturally cultivated herb. It is produced in chemical or pharmaceutical facilities through sublimation of mercury, alum (or chalcanthite), and salt. Major production areas historically include Hubei, Hunan, Shanxi, Hebei, and Yunnan provinces, as well as Tianjin. There is no 'dao di' (terroir) concept in the usual sense, though products from Hubei and Hunan have traditionally been considered standard.

Quality indicators

High-quality Qing Fen appears as large, intact flakes or snowflake-shaped crystalline pieces with a bright, clean white colour and silvery lustre. The pieces should be light in weight and crumble easily into fine white powder when rubbed between the fingers. It should be odourless with only a faint, bland taste (though it should never be tasted due to toxicity). There should be no visible mercury droplets (free metallic mercury beads indicate poor preparation). The product should not appear yellowed, grey, or darkened, as discolouration indicates light-induced decomposition into the far more toxic mercuric chloride and metallic mercury. Store away from light in sealed, dry containers.

Classical Texts

Key passages from the classical Chinese medical texts that describe Qing Fen and its therapeutic uses

Ben Cao Shi Yi (《本草拾遗》, A Supplement to Materia Medica, Tang Dynasty, Chen Cangqi)

"通大肠，转小儿疳并瘰疬，杀疮疥癣虫及鼻上酒齄，风疮瘙痒。"

"Frees the Large Intestine, transforms childhood malnutrition (gan) and scrofula (luo li), kills parasites of sores, scabies, and tinea, as well as rosacea on the nose, and wind sores with itching."

Ben Cao Gang Mu (《本草纲目》, Compendium of Materia Medica, Ming Dynasty, Li Shizhen)

"水银乃至阴毒物，因火煅丹砂而出，加以盐矾炼而为轻粉……其性走而不守，善劫痰涎，消积滞……若服之过剂，或不得法，则毒气被蒸，窜入经络筋骨，莫之能出，痰涎既去，血液耗亡，筋失所养，营卫不从，变为筋挛骨痛，发为痈肿疳漏……其害无穷。"

"Mercury is a substance of extreme Yin toxicity... [Qing Fen's] nature is mobile and restless. It excels at seizing phlegm and saliva and dissolving accumulations... If taken in excess or improperly, its toxic vapour steams into the channels, sinews, and bones and cannot be expelled. Once the phlegm is gone, the Blood and fluids are exhausted, the sinews lose their nourishment... it transforms into sinew contracture and bone pain, develops into abscesses and fistulae... its harm is limitless."

Zhang Yuansu (张元素, Jin Dynasty physician)

"洁净府，去膀胱中垢腻。"

"Cleanses the Pure Reservoir (Bladder), and removes filth and grease from the Bladder."

Yi Xue Ru Men (《医学入门》, Introduction to Medicine, Ming Dynasty)

"轻粉，经云利大肠，东垣又云抑肺而敛肛门……盖轻粉经火本燥，原自水银性冷，用之于润药则利，用之于涩药则止。"

"The classics say [Qing Fen] frees the Large Intestine, while [Li] Dongyuan says it suppresses the Lung and restrains the anus... Since Qing Fen is inherently drying from fire processing, yet originates from the cold nature of mercury, when used with moistening herbs it purges, and when used with astringent herbs it checks."

Ben Cao Jing Shu (《本草经疏》, Commentary on the Classic of Materia Medica, Ming Dynasty, Miao Xiyong)

"凡闭结由于血虚不能润泽；小儿疳病，脾胃两虚；小儿慢惊，痰涎壅上；杨梅结毒，发于气虚久病之人，咸不宜服。"

"In all cases of constipation from Blood deficiency failing to moisten; childhood malnutrition with dual Spleen and Stomach deficiency; childhood slow convulsions with phlegm congestion above; or syphilitic toxic nodules arising in those who are Qi-deficient and chronically ill: none of these are suitable for taking [Qing Fen]."

Historical Context

The history and evolution of Qing Fen's use in Chinese medicine over the centuries

Qing Fen was first recorded in the Tang Dynasty text Ben Cao Shi Yi (《本草拾遗》, c. 739 CE) by Chen Cangqi, where it appeared under the name Fen Gong (汞粉, "mercury powder"). It has accumulated numerous alternative names over the centuries, including Qiao Fen (峭粉), Shui Yin Fen (水银粉), Ni Fen (腻粉), Yin Fen (银粉), and Sao Pen (扫盆). The name Qing Fen (轻粉, literally "light powder") refers to its remarkably light, snowflake-like crystalline form that floats gently when disturbed. In Western chemistry it is known as calomel, a name likely derived from the Greek kalos (beautiful) and melas (black), referring to how it turns black when exposed to ammonia.

Qing Fen held a particularly important place in historical Chinese medicine for treating syphilis (杨梅疮, "yang mei chuang"), which spread widely in China from the late 15th century onward. Both in China and in the West, mercury compounds were for centuries the primary treatment for syphilis before modern antibiotics. Li Shizhen devoted extensive commentary to Qing Fen in the Ben Cao Gang Mu (1578), detailing its production method and its clinical uses while issuing one of the most famous and thorough warnings about mercury toxicity in classical Chinese medicine. He described vividly how overuse or improper use causes the toxic vapour to penetrate the channels and bones, leading to irreversible damage. The Song Dynasty physician Chen Wenzhong also warned specifically against using Qing Fen in children, noting that it "descends phlegm but damages Heart Qi" and can cause devastating harm to infants.

Interestingly, mercury-based medicine was used in parallel across multiple civilizations. In Indian Ayurvedic and Unani traditions, a substance called rasakarpura ("mercury camphor") closely resembles Qing Fen and was similarly used for syphilis and skin conditions. In Western medicine, calomel was one of the most widely prescribed drugs from the 16th through the 19th century, used as a purgative, antiseptic, and "cure-all" before its dangers were recognized. Today, due to its known toxicity, internal use of Qing Fen has been largely abandoned in modern clinical practice, though it occasionally appears in topical preparations for dermatological conditions under strict supervision.

Modern Research

2 published studies investigating the pharmacological effects or clinical outcomes of Qing Fen

Mercury and Mercury-Containing Preparations: History of Use, Clinical Applications, Pharmacology, Toxicology, and Pharmacokinetics in Traditional Chinese Medicine (Review, 2022)

Qiu Y, Liu Y, Li W, et al. Frontiers in Pharmacology, 2022, 13: 837498

A comprehensive review covering the historical use, pharmacological mechanisms, toxicological profiles, and pharmacokinetics of mercury-containing TCM preparations including Qing Fen (calomel). The paper documents antimicrobial activity of mercury preparations against various pathogens, while detailing the serious toxicity risks including renal tubular necrosis, neurotoxicity, and cumulative poisoning. It emphasises the need for strict dosage control and modern safety monitoring.

PubMed

Mercury Toxicity and Contamination of Households from the Use of Skin Creams Adulterated with Mercurous Chloride (Calomel) (Case Series, 2015)

Gonzalez-Estrada A, et al. International Journal of Environmental Research and Public Health, 2015, 12(9): 10943-10954

Documented multiple cases of mercury poisoning among families in California from skin creams containing mercurous chloride (calomel). Users showed urine mercury levels of 37 to 482 micrograms per gram creatinine, and household air mercury levels exceeded safe limits. The study demonstrated that even topical calomel use can cause significant systemic mercury absorption and household contamination affecting non-users.

PubMed

Research on individual TCM herbs is growing but still limited by Western clinical trial standards. These studies provide emerging evidence and should be considered alongside practitioner expertise.