Traditionally used for
- Cough & breathing
- Energy & fatigue
Cautions & contraindications
- Toxic — professional use only
☯ TCM Properties
Descends Qi; Descends Qi and Transforms Phlegm; Expels Parasites; Resolves Toxicity; Subdues Floating Yang
Traditional Chinese Uses
Hei Xi (black tin, stannum) is a warm, heavy metallic substance used in Chinese medicine as a profound Kidney Yang tonic that anchors Qi and descends rebellious Qi from the Lungs. It is used for the most severe patterns of Kidney Yang deficiency where Kidney Qi fails to grasp and anchor Lung Qi — resulting in chronic wheezing, breathlessness, and the sensation of Qi rushing upward. As a heavy metal, it requires careful processing and professional administration and is used in pill form, never decocted.
Relationships
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Botanical Description
Hei Xi is the traditional Chinese pharmacopoeial name for metallic lead, historically prepared by smelting the sulfide ore galena (PbS). Pure lead is a soft, dense, malleable post-transition metal with a bluish-white color on a fresh cut that quickly tarnishes to a dull greyish patina on exposure to air. It has a density of about 11.34 g/cm3, a low melting point of 327 degrees Celsius, and is extremely heavy for its size; it can be cut with a knife and leaves a grey mark when rubbed on paper. The metal is highly resistant to corrosion in moist air owing to a protective oxide-carbonate film. Lead and all of its compounds are cumulatively toxic to the nervous, hematopoietic, and renal systems; modern practice strongly discourages any internal medicinal use.
Active Constituents
Elemental lead (Pb)
Native heavy metal, smelted from galena (PbS)Concentration: The drug is metallic lead; refined lead is 99% or more Pb by mass
There is no therapeutic constituent here to describe. Lead is a cumulative poison with no known physiological role and no established threshold below which exposure is safe; the World Health Organization states plainly that no level of lead exposure is known to be without harmful effects. Any dose of this drug adds irreversibly to the body's lead burden, which is stored in bone with a half-life measured in decades and re-released during pregnancy, lactation, immobilisation and osteoporosis.
Lead(II) oxide and lead carbonate surface corrosion products (litharge, massicot, cerussite)
Lead oxides and carbonatesConcentration: Variable surface layer on metallic lead, increased by heating, grinding and long storage
Metallic lead tarnishes to oxide and carbonate, and these are far more soluble in gastric acid than the metal itself, converting readily to absorbable lead chloride. The finer the powder and the more oxidised the surface, the greater the absorbed fraction. Grinding and fusing the metal, which is exactly what traditional processing does, maximises this.
Lead(II) sulfide formed on fusion with sulfur
Metal sulfideConcentration: Principal phase of the classically processed drug, in which lead is melted together with sulfur (Liu Huang)
The classical Hei Xi Dan method fuses lead with sulfur, returning the metal to something close to the galena it was smelted from. As with cinnabar, the low solubility of the sulfide is the implicit safety argument, and as with cinnabar it is only partial: gastric acid, particle size, and any oxidised fraction all defeat it, and lead differs from mercury in having no threshold of safety at all.
Silver, antimony, arsenic, bismuth, cadmium and zinc smelter impurities
Ore and smelting impurity loadConcentration: Variable and wholly uncontrolled in artisanally produced material
Galena is the world's principal silver ore and routinely carries antimony, arsenic, bismuth, cadmium and zinc. Lead recovered outside a regulated refinery therefore delivers an unspecified mixture of additional toxic metals, of which cadmium and arsenic are the most consequential. Nothing in traditional processing removes them.
⚠ Drug Interactions
Any concurrent medicine, food or supplement (absolute prohibition rather than an interaction)
This entry exists because the honest answer for Hei Xi is not a list of pairings but a prohibition. Lead binds sulfhydryl groups indiscriminately, inhibits delta-aminolevulinic acid dehydratase and ferrochelatase in haem synthesis, substitutes for calcium in neuronal signalling and in bone, and crosses both the placenta and the blood-brain barrier. Pooled analysis of seven prospective birth cohorts found IQ loss associated with blood lead below 7.5 micrograms per decilitre with no evidence of a threshold, and the loss per unit of lead was steepest at the lowest exposures. Meanwhile the Chinese Pharmacopoeia sets a lead limit of 5 mg/kg for medicinal materials; a drug that is metallic lead exceeds that limit by a factor of roughly two hundred thousand. There is no dose of this substance that is compatible with the standards the same pharmacopoeia applies to every other drug on the shelf.
Clinical note: Do not dispense. If a patient reports having taken Hei Xi, Hei Xi Dan or any lead-containing preparation, stop it, measure blood lead and a full blood count, and refer to clinical toxicology. Screen household members who shared the preparation, as reported cases include asymptomatic spouses with markedly raised blood lead.
Aconite (Fu Zi) and sulfur (Liu Huang) as co-ingredients of Hei Xi Dan
Hei Xi Dan pairs lead with processed aconite and sulfur. The formula therefore carries simultaneous risks with entirely different time-courses: aconitine cardiotoxicity is acute and dose-dependent within hours, lead toxicity is cumulative over months. A course judged safe on the basis of no acute event says nothing about the lead burden accrued.
Clinical note: Hei Xi Dan is of historical interest only. Where a modern manufacturer still supplies something under that name, demand elemental analysis before assuming the lead has been omitted.
Iron deficiency and iron-deficiency anaemia (and by extension iron supplementation status)
Lead is taken up across the intestinal brush border largely by divalent metal transporter 1, the same transporter that carries iron. Iron deficiency upregulates DMT1 and markedly increases lead absorption, so the patients most likely to be prescribed a blood-building formula are the patients who will absorb the most lead from it. Lead then worsens the anaemia by inhibiting haem synthesis, closing a vicious circle: the anaemia that prompts treatment is deepened by the treatment.
Clinical note: Anaemia with basophilic stippling on the blood film in a patient taking traditional medicine should prompt a blood lead measurement before it prompts iron. Correcting iron status reduces further lead uptake but does not remove what is already stored.
Chelating agents (succimer/DMSA, calcium disodium EDTA, D-penicillamine)
These are the treatment for lead poisoning. Published cases of lead poisoning from traditional medicine document normalisation of blood lead and resolution of colic and anaemia after repeated chelation rounds, once the source was stopped. Chelation lowers blood lead but mobilises skeletal stores and does not reverse established neurodevelopmental injury.
Clinical note: Chelation is a toxicology decision made on blood lead and clinical severity, not a herbalist's. The first and non-negotiable step is removing the source.
Lead-contaminated or lead-adulterated herbal products generally
Lead reaches patients through traditional medicine far more often as an adulterant, a lead-containing paste or base, or a homemade preparation than as a named drug. Documented cases include a 66-year-old man and his asymptomatic wife with blood lead of 657 and 488 micrograms per litre from a homemade preparation later assayed at more than 4,000 mg/kg lead, and a 21-year-old man with colic, anaemia, liver injury and blood lead of 1,268 micrograms per litre after a year of a preparation taken for acne. The clinical presentation is abdominal colic with constipation and anaemia, and it is routinely mistaken for a surgical or gastroenterological problem.
Clinical note: Consider lead in any patient on traditional medicine presenting with unexplained abdominal colic, constipation and anaemia, particularly where the product was homemade or came from an unregulated clinic. Ask for the actual product and have it assayed.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| not recommended | Not established — should not be dispensed | Daily | — | — | **Lead metal (Plumbum).** No ChP monograph. Lead is a cumulative neurotoxin with no safe intake; internal use is indefensible and even traditional external use in plasters carries absorption risk. Historically implicated in fatal poisonings from 黑锡丹. No dose given. See also qian-dan (Pb₃O₄) and mi-tuo-seng (PbO). |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Heavy descending of lead combined with the hot life-gate-warming action of sulphur, which warms Kidney yang and draws rebellious qi down to grasp qi.
Upper excess and lower deficiency with wheezing from Kidney failing to grasp qi. Both are toxic (lead and sulphur); short-term use only, contraindicated in pregnancy.
Core pair of a classical formula — Hei Xi Dan, Tai Ping Hui Min He Ji Ju Fang
Evidence Tier
Moderate evidence · 4 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
0
Other clinical trial
0
Observational / case report
4
3 verified · 1 unverified
Show 4 studies
- Low-Level Environmental Lead Exposure and Children's Intellectual Function: An International Pooled Analysis
- Lead Poisoning Caused by Traditional Chinese Medicine: A Case Report and Literature Review
- Non-occupational lead poisoning associated with traditional Chinese medicine: A case report
- Unmasking herbal medication-induced lead poisoning in a geriatric patient with gastrointestinal symptoms
In vitro / animal
0
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Low-Level Environmental Lead Exposure and Children's Intellectual Function: An International Pooled Analysis
Pooled analysis of seven international prospective birth cohorts (1,333 children) found lead-associated intellectual deficits in children whose maximal blood lead stayed below 7.5 micrograms per decilitre, with no evidence of a threshold and with the steepest decrement per unit of lead at the lowest exposures. This is the study behind the modern position that no safe blood lead level exists. An erratum correcting analytical errors was published in the same journal in 2019 (doi 10.1289/EHP5685); the paper was corrected, not retracted, and its central conclusion stands.
Lead Poisoning Caused by Traditional Chinese Medicine: A Case Report and Literature Review
Single case report with literature review. A 66-year-old man presented with periumbilical pain and constipation after eight months of a homemade traditional preparation; blood lead was 657 micrograms per litre and his asymptomatic wife's was 488. The preparation assayed at more than 4,000 mg/kg lead. Symptoms resolved and blood lead normalised after three rounds of chelation. The authors call for tighter regulation of small private clinics and note that lead reaches patients through lead-containing bases and pastes added to herbs, intentionally or otherwise.
Non-occupational lead poisoning associated with traditional Chinese medicine: A case report
Single case report. A 21-year-old man with severe periumbilical colic after a year of traditional medicine taken for facial acne had anaemia, liver injury, basophilic stippling on bone marrow smear and a blood lead concentration of 1,268.4 micrograms per litre. The presentation is the classic lead colic that is repeatedly mistaken for an acute abdomen.
Unmasking herbal medication-induced lead poisoning in a geriatric patient with gastrointestinal symptoms
Single case report in a man in his seventies presenting with vomiting, constipation and anaemia; blood and urine lead were raised and the herbal preparation he had been taking assayed high for lead. He improved with supportive care, nutritional supplementation and calcium disodium EDTA chelation. Included here because the geriatric presentation is even more often misattributed than the young-adult one.
Historical Texts
Ben Cao Gang Mu (Li Shizhen)
Ming dynasty, 1596Taiping Huimin Heji Ju Fang (imperial formulary of the Bureau of People's Welfare Pharmacies)
Song dynasty, compiled from 1078 and issued in the twelfth centuryWorld Health Organization position on lead
Modern, currentReferences
- World Health Organization. Lead poisoning . WHO Fact Sheets (2024)
- Lanphear BP, Hornung R, Khoury J, Yolton K, Baghurst P, Bellinger DC, Canfield RL, Dietrich KN, Bornschein R, Greene T, Rothenberg SJ, Needleman HL. Erratum: “Low-Level Environmental Lead Exposure and Children's Intellectual Function: An International Pooled Analysis” . Environmental Health Perspectives (2019) [DOI]
- Inada I, Kiuchi F, Urushihara H. Comparison of Regulations for Arsenic and Heavy Metals in Herbal Medicines Using Pharmacopoeias of Nine Counties/Regions . Therapeutic Innovation and Regulatory Science (2023) [DOI]
- Inada I, Kiuchi F, Urushihara H. Correction: Comparison of Regulations for Arsenic and Heavy Metals in Herbal Medicines Using Pharmacopoeias of Nine Counties/Regions . Therapeutic Innovation and Regulatory Science (2023) [DOI]
- Waldron HA. Lead Poisoning in the Ancient World . Medical History (1973) [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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