Mi Tuo Seng (Litharge)

Chinese Herb Actions

Chinese Herb Contraindications & Cautions

• Is Mi Tuo Seng (Litharge) safe to use today?

  No — litharge is essentially pure lead(II) oxide, and no level of lead exposure is considered safe. Even historical, external-only application carries a real risk of lead absorption through skin (especially broken or damaged skin) and of accidental ingestion or inhalation of the powder, particularly by children. Modern case reports repeatedly document lead poisoning traced to lead-containing traditional Chinese medicine products, including topical preparations (see Research, below).

  • No safe threshold — the U.S. CDC and EPA state there is no known safe blood lead level in children; low-level exposure is linked to developmental and cognitive harm.
  • Classical incompatibility — pre-modern Chinese pharmacology lists Mi Tuo Seng as antagonistic to Lang Du (Euphorbia fischeriana) in the traditional “Nineteen Medicinal Antagonisms” (十九畓) mnemonic; this is a historical compounding rule, not a modern-verified pharmacological interaction.
  • Not equivalent to Hong Dan — Mi Tuo Seng (litharge, PbO) is a distinct mineral from Hong Dan / Qian Dan (red lead, Pb3O4, “minium”), another toxic lead-oxide substance sometimes used externally in the same historical tradition; the two are occasionally conflated in secondary sources.

  Source: CDC, Blood Lead Reference Value update, MMWR 70(43):1509–1512 (2021); classical Nineteen Antagonisms (十九畓) list as reported by multiple online sources and other TCM references. Reference/safety information only, not usage guidance.

Chinese Herb Toxicity & Overdose

• Mi Tuo Seng is essentially pure lead(II) oxide (PbO, CAS 1317-36-8) — a recognized heavy-metal toxin with no established safe exposure level. Lead compounds are absorbed through inhalation, ingestion, and, for fine mineral powders applied to skin, dermal contact — especially where skin is broken. Once absorbed, lead distributes to blood, soft tissue, and bone, where it can be stored and slowly released for years.

  • Target systems — the nervous system (especially developing brains in children), kidneys, blood (lead interferes with heme synthesis, causing anemia), and reproductive system are the best-documented targets of lead toxicity.
  • Carcinogenicity — the International Agency for Research on Cancer (IARC, 2006 monograph) classifies inorganic lead compounds as Group 2A, “probably carcinogenic to humans”; the U.S. National Toxicology Program lists lead and lead compounds as “reasonably anticipated to be human carcinogens.”
  • No safe threshold — the CDC/EPA position is that no blood lead level in children is known to be safe; the CDC’s current blood lead reference value (used to flag elevated exposure) is 3.5 µg/dL.

  Source: ATSDR, Toxicological Profile for Lead (2020); National Toxicology Program, Report on Carcinogens, 15th ed.; IARC Monograph Volume 87 (2006), Inorganic and Organic Lead Compounds; CDC, Blood Lead Reference Value update, MMWR 70(43):1509–1512 (2021); lead(II) oxide chemical identity, CAS 1317-36-8. Reference toxicology information, not a clinical safety guarantee.

• This herb is considered toxic.
  (while some Chinese herbs are toxic, it must be noted that many come prepared, or are combined, to mitigate their toxicity)

Herb-Drug Interactions

• No modern clinical herb–drug interaction studies exist for Mi Tuo Seng, because it has no accepted internal or systemic therapeutic use in contemporary practice. The relevant concern is not a pharmacologic interaction but cumulative heavy-metal exposure: patients undergoing chelation therapy, those with impaired renal function (lead is renally excreted), or anyone with other sources of lead exposure would face compounded risk from any lead absorbed via this substance. (Flagged for practitioner awareness, not a demonstrated drug interaction.)

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on litharge (lead(II) oxide) toxicity?

  Yes — an extensive toxicology literature documents lead oxide and lead-containing traditional medicines as a preventable source of poisoning, though little research targets Mi Tuo Seng by name. Most directly relevant studies concern lead poisoning traced to traditional Chinese medicine products generally, plus the broader toxicological and regulatory profile of inorganic lead compounds.

  • Case reports (TCM-associated lead poisoning) — a 2022 case report describes a patient with severe lead poisoning (blood lead 1,268.4 µg/L against a <400 µg/L reference range) after roughly a year of oral TCM pills/powder taken for acne, found to contain 8,421 µg/g lead; the same report separately discusses Hong Dan (red lead, Pb3O4), a related lead-oxide mineral, as a known externally-applied TCM substance for eczema. A separate 2017 case report describes chronic use of a homemade TCM preparation producing a blood lead level of 657 µg/L in the patient, with the medicine itself measured at over 4,000 mg/kg lead.
  • Systematic toxicology (inorganic lead) — the ATSDR federal toxicological profile and the IARC/NTP carcinogenicity evaluations (see Toxicity, above) summarize decades of human and animal evidence on lead absorption, organ toxicity, and cancer risk that apply directly to lead(II) oxide as an inorganic lead compound.

  Taken together, this literature supports treating any lead-oxide mineral, including Mi Tuo Seng, as a documented toxic-exposure risk rather than a substance with an established modern safety margin.

  Note: We could not locate toxicology research specific to Mi Tuo Seng/litharge by name in PubMed/PMC. The case reports and toxicology sources cited below concern lead oxide and lead-contaminated TCM products generally, which we judge directly applicable to this chemically identical substance, per the site’s discrepancy rule.

  Sources: PMID 36176514, PMC 9513390 (Frontiers in Public Health, 2022 — TCM-associated lead poisoning case report); PMID 29081456, DOI 10.1620/tjem.243.127 (Tohoku Journal of Experimental Medicine, 2017 — TCM lead poisoning case report and literature review); ATSDR, Toxicological Profile for Lead (2020); National Toxicology Program, Report on Carcinogens, 15th ed.; IARC Monograph Volume 87 (2006), Inorganic and Organic Lead Compounds. Research/regulatory context, not a therapeutic or safety claim.

Chinese Herb Notes

• Is Mi Tuo Seng the same as other lead-based Chinese minerals?

  No — Mi Tuo Seng (litharge) is lead(II) oxide (PbO), a distinct substance from Hong Dan / Qian Dan (red lead, Pb3O4, “minium”), another toxic lead-oxide mineral used externally in historical Chinese materia medica. Both are inorganic lead compounds with overlapping historical topical uses on sores and skin conditions, and both carry the same fundamental lead-toxicity concerns described above; they should not be treated as interchangeable when reading historical formulas or toxicology reports.

  This site’s own record lists Mi Tuo Seng under “Substances for External Application,” consistent with its documented historical use pattern; no formulas in the current database list Mi Tuo Seng as an ingredient.

  Source: this site’s own reference record (category and identity fields); case-report literature distinguishing Mi Tuo Seng from Hong Dan (Research section, above).

This herb is toxic or restricted in the United States