Traditionally used for
- Eye health
- Skin
Cautions & contraindications
- Pregnancy
- Breastfeeding
- Young children
☯ TCM Properties
Clears toxins and brightens the eyes; Brightens the Eyes and Removes Visual Obstructions; Dries Dampness and Stops Itching; Promotes Tissue Regeneration and Heals Sores; Stops Bleeding
Traditional Chinese Uses
Lu Gan Shi (smithsonite, calamine) is a cold, sweet mineral substance used in Chinese medicine primarily as a topical remedy for eye conditions and inflammatory skin diseases. Applied externally, it clears Liver Heat from the eyes, reduces redness, and relieves eye pain and inflammation. For skin conditions, it absorbs moisture, cools inflammation, and dries weeping lesions — making it important in formulas for eczema, sores, and itching skin. Internally it clears Liver Heat for certain eye conditions.
Relationships
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Botanical Description
Lu Gan Shi is the traditional Chinese pharmacopoeial name for smithsonite, a zinc carbonate mineral with the formula ZnCO3 that forms in the oxidized zones of zinc sulfide ore deposits. It typically occurs as botryoidal, reniform, or stalactitic masses rather than as well-formed crystals, and may also appear as earthy crusts or compact granular aggregates. Colors range from greyish-white and pale yellow to greenish-blue, pink, and brown depending on minor impurities of copper, iron, cobalt, or cadmium; the medicinal grade is usually a pale greyish-white to yellowish-white. The mineral has a hardness of about 4 to 4.5 on the Mohs scale, a vitreous to dull luster, and a brittle fracture. For medicinal preparation the raw mineral is calcined, then quenched and levigated to yield a fine, soft, slightly gritty powder.
Active Constituents
Hydrozincite, Zn5(CO3)2(OH)6 - the mineral of most commercial Lu Gan Shi
Basic zinc carbonate mineralConcentration: X-ray diffraction of market samples found hydrozincite to be the main mineral of raw Calamina, with smithsonite detected in only some samples
This is the most important single fact about the drug and it contradicts the name it is sold under. The Chinese Pharmacopoeia defines Lu Gan Shi as smithsonite, but a survey of market samples by Song and colleagues found the mineral origin of mainstream commercial Calamina inconsistent with the pharmacopoeial stipulation, and recommended that hydrozincite be formally approved and written into the monograph. Pharmacologically the two behave alike - both decompose to zinc oxide on calcination - so this is a provenance and contaminant question rather than an efficacy one, but it means the mineral named in the monograph and the mineral in the jar are usually not the same.
Smithsonite, ZnCO3
Zinc carbonate mineral, the nominal pharmacopoeial sourceConcentration: The species named in the Chinese Pharmacopoeia definition, but detected in only a minority of market samples; dwindling smithsonite resources are the reason given for the substitution
The mineral the drug is supposed to be. Both smithsonite and hydrozincite are secondary carbonates from the oxidised cap of lead-zinc sulfide orebodies, which is why the substitution does not change the essential safety story: the contaminants come from the deposit type, not from which carbonate crystallised.
Zinc oxide (ZnO)
Metal oxide; the assayed active and the product of calcinationConcentration: The Chinese Pharmacopoeia specifies not less than 40.0 percent ZnO calculated on the dried drug. Calcined Duan Lu Gan Shi is substantially converted to ZnO.
Zinc oxide is what the drug does: a mild astringent and protectant that absorbs exudate, reduces friction and itch, and supports re-epithelialisation. It is essentially not absorbed through intact skin and is the reason the drug is safe enough for a nappy area when the mineral is clean. Calcination is not cosmetic - it converts the carbonate to the oxide and is what the assay measures.
Lead, incorporated in the mineral lattice
Toxic heavy metal, present as isomorphous substitution for zinc rather than as a separable impurityConcentration: No lead limit exists in the Calamina monograph. Song and colleagues found lead and cadmium generally high across market samples of both raw and calcined Calamina and explicitly recommended that limit standards for Pb and Cd content be formulated - a recommendation that only makes sense because there are none.
Electron probe microanalysis shows lead sitting inside the hydrozincite crystal as an isomorphous substitute for zinc, distributed evenly, with a constant ZnO to PbO ratio across measurement points. It is therefore not removable by sorting or washing the raw mineral. Calcination at 800 degrees C breaks the hydrozincite lattice, converting the zinc to ZnO and the lead to PbO and decoupling their distributions, after which water levigation can carry some of the lead away. This is the mechanistic justification for the classical calcine-and-levigate processing, and it is also why an under-calcined or unlevigated product is a lead hazard rather than merely an inferior drug.
Cadmium
Toxic heavy metal co-occurring with zinc in all zinc oresConcentration: No cadmium limit exists in the Calamina monograph. Market survey found cadmium generally high in both raw and calcined material.
Cadmium substitutes for zinc throughout the zinc ore system because the two ions are chemically alike, and it follows zinc into the secondary carbonates of the oxidised zone; work on smithsonite-spiked soils confirms natural particulate cadmium travelling with the mineral. Unlike lead, cadmium is not addressed at all by the classical processing rationale, and its boiling point means calcination will not reliably remove it. On broken or eroded skin, and in the eye, this is the least controlled exposure the drug carries.
Hemimorphite, calcite, dolomite and quartz
Accessory and gangue minerals of the oxidised zinc oreConcentration: Identified as the principal impurity minerals of raw Calamina by X-ray diffraction; hemimorphite, Zn4Si2O7(OH)2·H2O, is itself a zinc mineral and contributes to the zinc assay without being the named source
Hemimorphite matters because it can carry a sample through a zinc-content assay while the sample is not the mineral the monograph names. It is one reason Song and colleagues called for identification methods with better specificity, alongside their finding that counterfeit Calamina products were widespread on the market.
Arsenic, copper and mercury
Further harmful elements measured in market surveys of the drugConcentration: Determined by ICP-MS, ICP-AES and atomic fluorescence in market samples; arsenic and copper were found elevated in some inferior-grade Calamina. No monograph limit for these elements in this drug could be verified. The general Chinese Pharmacopoeia values quoted for Chinese medicines - Pb 5, Cd 1, As 2, Hg 0.2 and Cu 20 mg/kg - are written for designated herbal pieces and are not applied to this mineral.
Recorded to make the negative explicit: this is a drug whose harmful-element content has been measured and found variable and sometimes high, and for which no binding elemental limit has been set. Absence of a limit is not evidence of a clean mineral - here it is documented evidence of the opposite.
Ferric oxide - the constituent of the Western drug that shares this name
Iron oxide colourant of a different, differently-defined articleConcentration: In British and United States pharmacopoeial calamine, the drug is prepared zinc oxide with a small proportion of ferric oxide, which gives the familiar pink lotion; it contains no zinc carbonate mineral at all
A name hazard rather than a constituent of Lu Gan Shi. Western calamine is a manufactured zinc oxide preparation with defined elemental purity; Lu Gan Shi is a mined carbonate ore with documented lead and cadmium and no elemental limits. Evidence about one should not be carried across to the other, and a Western calamine lotion is not a substitute for, nor equivalent to, the Chinese mineral drug of the same name.
⚠ Drug Interactions
Any concurrent lead exposure, and use in children, pregnancy or breastfeeding
Lead in Lu Gan Shi is lattice-bound in the mineral rather than adventitious, and market surveys report it as generally high across both raw and calcined product. There is no permitted-level standard for lead in this monograph. Lead has no safe exposure threshold in children, and the classical indications - weeping sores, eczema, ulcerated skin, eye disease - are precisely the situations where the skin barrier is absent and prolonged, repeated application over broad areas is expected.
Clinical note: Do not use Lu Gan Shi on children, in pregnancy or during breastfeeding, and do not use it long-term on broken skin in anyone. Where a topical zinc astringent is genuinely indicated in these groups, use a pharmaceutical zinc oxide preparation of defined purity instead.
Ophthalmic application, including the classical eye preparations for red eyes and visual obstruction
The eye indications are among the oldest recorded for this drug and are still listed in its functions, but they place an unstandardised mined mineral, with measured lead and cadmium and no elemental limits, in direct and repeated contact with ocular surfaces. Water levigation reduces particle size, which improves the cosmetic feel and the classical rationale for eye use, but it does not certify the metal content, and calcination does not reliably remove cadmium.
Clinical note: Do not compound or dispense Lu Gan Shi for ophthalmic use. Modern ophthalmic preparations are sterile and elementally specified; this drug is neither.
Counterfeit and substituted Calamina on the market
The market survey that measured this drug's harmful elements also reported that counterfeit Calamina products were widespread, that the mainstream commercial mineral is not the one the pharmacopoeia defines, and that a proportion of calcined Calamina had been improperly or inadequately processed. Under-calcination matters specifically: it is calcination that breaks the hydrozincite lattice and separates lead from zinc so that levigation can remove some of it, so an inadequately fired product retains its lead in the least removable form.
Clinical note: Source only from a supplier who can produce X-ray diffraction identification and an elemental analysis for lead and cadmium. A zinc oxide assay alone does not establish identity, because hemimorphite and other zinc minerals will pass it.
Western calamine lotion (zinc oxide with ferric oxide) and topical zinc oxide preparations
The two drugs share a name and an appearance but not a definition. Western pharmacopoeial calamine is manufactured zinc oxide with ferric oxide and has specified elemental purity; Lu Gan Shi is a mined zinc carbonate ore with documented lead and cadmium and no elemental limits. Clinical evidence generated with Western calamine lotion, which is most of what exists, does not transfer to Lu Gan Shi on the safety side, though the zinc oxide pharmacology is common to both.
Clinical note: State explicitly on the prescription which article is meant. If the intent is the well-characterised topical astringent, prescribe zinc oxide or Western calamine and not the mineral drug.
Occlusive dressings, nappy occlusion and application to burns, ulcers or eroded skin
Zinc oxide itself does not meaningfully penetrate intact skin, and human penetration studies of topical zinc oxide find it stays in the stratum corneum. That protective assumption fails where the barrier is gone. Occlusion, denuded ulcer beds and burn surfaces are absorptive, and it is the lead and cadmium travelling with the mineral, not the zinc, that make this a concern for Lu Gan Shi specifically rather than for zinc oxide generally.
Clinical note: Restrict to small areas of intact or lightly abraded skin, do not occlude, and do not apply to burns or chronic ulcers. Choose a defined zinc oxide preparation where a large or denuded area needs covering.
Processing with Huang Lian Tang or San Huang Tang quenching, versus plain calcination
Classical processing of Lu Gan Shi includes calcination followed by quenching in vinegar or in a decoction of Huang Lian, or of Huang Lian, Huang Bai and Da Huang, before water levigation; modern analytical work has characterised what the decoction-quenched articles actually are. The processed variants are not simply the calcined mineral, and a formula that specifies the San Huang Tang quenching is not calling for plain Duan Lu Gan Shi.
Clinical note: Dispense the processed form the formula names. Note that whichever quench is used, none of these processes is a substitute for an elemental analysis.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| topical | See note — route-specific dosing | Daily | — | — | 中国药典 2020 【用法与用量】外用适量。 【性味与归经】甘，平。归肝、脾经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Moderate evidence · 3 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
1
1 verified · 0 unverified
Other clinical trial
1
0 verified · 1 unverified
Observational / case report
0
In vitro / animal
0
Other / unclassified
1
1 verified · 0 unverified
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Calamine Lotion to Reduce Skin Irritation in Children with Cast Immobilisation
250 children aged 6 to 15 in cast immobilisation for limb fractures were assigned to calamine (122) or no calamine (128), with itch, sweat and heat self-graded and skin lesions recorded by the plaster technician at cast removal. The calamine group developed fewer skin lesions (1 versus 9, odds ratio 0.115, p equals 0.009) and reported less itch during casting (mean difference 0.74, p less than 0.0001). This is a Western calamine lotion, a zinc oxide preparation, not the Chinese mineral drug, and the allocation was by assignment rather than randomisation; it is the best positive clinical signal available for topical calamine and should be read with both qualifications attached.
Does the use of calamine or antihistamine provide symptomatic relief from pruritus in children with varicella zoster infection?
A structured best-evidence review of the commonest paediatric indication for calamine, which found no adequate trial evidence that calamine relieves the itch of chickenpox. It is included deliberately as the negative counterweight: the drug's most familiar use is supported by custom rather than by data, and a practitioner weighing a lead-bearing mineral against a well-tolerated modern alternative should know that the benefit side of the ledger is thin.
Open-label, randomised, multicentre crossover trial assessing two-layer compression bandaging for chronic venous insufficiency: results of the APRICOT trial
Randomised crossover trial in 39 patients with chronic venous insufficiency comparing a calamine-impregnated two-layer compression bandage with a non-calamine comparator, each worn for three weeks, with severity of pruritus as the primary outcome. No significant difference was found on any validated pruritus measure (p equals 0.24 in 35 completers), although 60 percent of patients definitely preferred the calamine bandage after trying both. Again a Western zinc oxide calamine rather than Lu Gan Shi, and again the objective antipruritic effect did not appear.
Historical Texts
Ben Cao Pin Hui Jing Yao (Collected Essentials of Materia Medica), Liu Wentai and colleagues
Ming, 1505Ben Cao Gang Mu (Compendium of Materia Medica), Li Shizhen
Ming, 1596Classical processing tradition: calcination, quenching in vinegar or in Huang Lian or San Huang decoction, then water levigation
Ming to Qing, transmitted in the processing literature from the 16th century onwardReferences
- Song GF; Zhang ZJ; Li RR; Song C; Lin RC. [Study on quality status of mineral medicine Calamina]. . Zhongguo Zhong Yao Za Zhi (China Journal of Chinese Materia Medica) (2020) [DOI]
- Song GF; Zhang ZJ; Li RR; Song C. Study on the Occurrence Forms and Distribution Characteristics of Zinc and Lead Before and After Calcination of Mineral Medicine Calamine . Spectroscopy and Spectral Analysis (2019)
- Zhang X; Chen L; Sun Y; Bai Y; Huang B; Chen K. Determination of zinc oxide content of mineral medicine calamine using near-infrared spectroscopy based on MIV and BP-ANN algorithm . Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (2018) [DOI]
- Meng XL; Ma JN; Guo XH; Liu BC; Cui NN; Li K; Zhang SS. Processing of calamine with modern analytical techniques: Processed with Huanglian Decoction (黄连汤) and Sanhuang Decoction (三黄汤) . Chinese Journal of Integrative Medicine (2017) [DOI]
- Li X; Wu L; Zhou J; Luo Y; Zhou T; Li Z; Hu P; Christie P. Potential environmental risk of natural particulate cadmium and zinc in sphalerite- and smithsonite-spiked soils . Journal of Hazardous Materials (2022) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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