Xiong Huang (Realgar)

Chinese Herb Actions

Chinese Herb Dosage

• Is there a safe home dose of Xiong Huang (Realgar)?

  No — this reference intentionally gives no dose or preparation instructions for Xiong Huang. As an arsenic-sulfide mineral, realgar has no consumer-safe self-administered dose. Historically it was used internally only in minute, practitioner-controlled quantities, and contemporary regulation restricts it to professional, prescription-only contexts.

  • Prescription-only in regulated jurisdictions — Hong Kong’s Chinese Medicine Ordinance lists realgar among the 31 Schedule 1 “potent/toxic” Chinese herbal medicines that may only be purchased against a registered Chinese medicine practitioner’s prescription, administered per that practitioner’s instructions.
  • Modern practice is external/topical only — consistent with this database’s own “Substances for External Application” classification; internal use is not covered here.
  • Never heated or decocted — see Cautions and Toxicity: heating oxidizes realgar into arsenic trioxide, a far more toxic and soluble compound.

  Source: Hong Kong Chinese Medicine Regulatory Office, “General Knowledge of Toxic Chinese Herbal Medicines” (Chinese Medicine Ordinance, Cap. 549, Schedule 1); toxicology literature below. Reference only — not usage or dosing guidance.

Chinese Herb Contraindications & Cautions

• Are there cautions or restrictions on Xiong Huang (Realgar)?

  Xiong Huang is an arsenic-sulfide mineral (properties recorded as Spicy, Bitter, Warm, Toxic) and is one of the most heavily restricted substances in Chinese materia medica. Traditional sources list it as contraindicated in pregnancy and in patterns of yin or blood deficiency. It is regulated as a controlled toxic substance in at least one major jurisdiction and has documented cases of serious harm even from external use.

  • Never heated, calcined, or decocted — heating oxidizes realgar’s arsenic sulfide into arsenic trioxide, a substantially more soluble and toxic arsenic compound; this prohibition is standard in Chinese pharmacognosy/processing literature.
  • Pregnancy — traditionally contraindicated.
  • Regulatory status (reference note) — Hong Kong’s Chinese Medicine Ordinance (Schedule 1) restricts realgar to prescription-only sale and use by a registered Chinese medicine practitioner.
  • Harm documented even from topical/external use — a fatal case of acute arsenic poisoning followed external (skin) application of a realgar-based folk ointment for psoriasis over about four days, and a literature review identified seven such external-use poisoning cases in China over a 30-year period. A separate fatal case of toxic epidermal necrolysis followed extensive topical use of a realgar-containing ointment over 18 days, with markedly elevated postmortem blood arsenic.
  • Long-term/repeated exposure risk — a case report describes multiple concurrent skin cancers (basal cell carcinoma, Bowen disease, squamous cell carcinoma) in a patient after approximately 15 years of realgar-containing medicine use for psoriasis.

  Source: traditional materia medica cautions; Hong Kong Chinese Medicine Regulatory Office (Schedule 1); PMID 31023496; PMID 24003889; PMID 38107294. Safety/regulatory reference, not medical advice.

Chinese Herb Toxicity & Overdose

• Realgar (As4S4) is an inorganic arsenic mineral and is classified as toxic; both traditional and modern sources treat it as a substance requiring strict control. Intact arsenic disulfide/tetrasulfide is poorly soluble in water, which limits (but does not eliminate) gastrointestinal absorption of the pure compound. However, commercial and unprocessed material commonly contains variable amounts of more soluble, more toxic inorganic arsenic impurities (such as arsenate and arsenite), and in the body realgar-derived arsenic is metabolized predominantly to dimethylarsenic acid.

  Heating is the critical hazard multiplier. Calcining or otherwise heating realgar oxidizes its arsenic sulfide into arsenic trioxide (Pi Shuang) — a far more water-soluble and acutely toxic arsenic compound — which is why fire processing/decoction of realgar is prohibited in Chinese pharmacognosy.

  Documented human harm:

  • Fatal acute arsenic poisoning following external (topical) use of a realgar-based folk remedy on skin, with a 30-year literature review identifying multiple comparable Chinese case reports.
  • A fatal case of toxic epidermal necrolysis after extensive dermal application of a realgar-containing ointment over 18 days; the ointment itself assayed at 4,229–45,427 ppm arsenic, and postmortem blood arsenic reached 1,225 µg/L.
  • Repeated oral dosing of a realgar-containing patent medicine (NiuHuangJieDu tablets) in healthy volunteers showed limited change in blood arsenic after a single dose, but pronounced accumulation with repeated dosing (accumulation index ~20.6) and a very long elimination half-life (~168 hours), indicating a real long-term accumulation risk even at recommended dosing.
  • Long-term/chronic exposure has been associated with arsenical keratosis and, in one case report, multiple concurrent cutaneous carcinomas after roughly 15 years of use.

  Source: PMID 31023496; PMID 24003889; PMID 35069195; PMID 38107294; PMID 25861951; DOI 10.1097/st9.0000000000000004 (toxicology review). Toxicology reference, not a safety guarantee for any use.

• 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 well-established clinical herb–drug interaction studies specific to Xiong Huang/realgar were identified in the literature reviewed. Given the documented systemic absorption and accumulation of arsenic with repeated exposure (see Toxicity), general toxicological reasoning would flag concurrent use of other arsenic-containing preparations, or conditions/agents that reduce renal clearance, as likely to compound systemic arsenic burden — this is a precautionary inference from toxicology data, not a demonstrated clinical drug interaction. (Flagged for practitioner/toxicologist confirmation; formal interaction studies appear to be lacking in the published literature.)

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 Xiong Huang (Realgar, arsenic sulfide As4S4)?

  Yes — research is concentrated in toxicology, pharmacokinetics, and preclinical anticancer mechanisms, with human data limited mainly to case reports of harm and one volunteer pharmacokinetic study; there are no clinical efficacy trials.

  • Human pharmacokinetics/accumulation — a study in healthy volunteers given realgar-containing NiuHuangJieDu tablets found limited blood-arsenic change after a single dose, but substantial accumulation and a very long elimination half-life (~168 hours) with repeated dosing, recommending explicit arsenic warnings for long-term use.
  • Chinese patent medicine survey — a review of realgar-containing patent medicines found wide variation in arsenic content and estimated daily arsenic intake, with a substantial share of products exceeding 10 mg/day arsenic exposure and roughly two-fifths marketed for children, concluding a potential long-term health hazard.
  • Case reports of harm — documented fatal acute arsenic poisoning from external (topical) use in psoriasis treatment; a fatal toxic-epidermal-necrolysis case from extensive dermal application; and a case of multiple cutaneous carcinomas after roughly 15 years of use.
  • Preclinical anticancer mechanism (in vitro) — laboratory (cell-culture) research reports that realgar induces death of acute promyelocytic leukemia cells via a Bcl-2/Bax/cytochrome-C/AIF apoptosis pathway; this is early-stage laboratory investigation, not clinical evidence, and is unrelated to any traditional external/topical use.
  • Formula-context animal study — mouse research on An Gong Niu Huang Wan found that co-formulated herbs measurably reduced the hepatorenal (liver/kidney) toxicity otherwise produced by its cinnabar and realgar content.
  • Comprehensive toxicology review — a 2023 review synthesizes realgar’s chemical characterization, arsenic metabolism (chiefly to dimethylarsenic acid), and toxicity mechanisms, concluding it is generally low-toxicity at controlled doses but that prolonged use poses meaningful risk.

  Human clinical evidence is limited to pharmacokinetic and harm-reporting studies; there is no clinical-trial evidence of therapeutic efficacy for any indication.

  Sources: PMID 35069195; PMID 25861951; PMID 31023496; PMID 24003889; PMID 38107294; PMID 36098742 (preclinical); PMID 29950994 (preclinical); DOI 10.1097/st9.0000000000000004. Research context, not a therapeutic claim.

Chinese Herb Notes

• How is Xiong Huang (Realgar) related to orpiment, cinnabar, and arsenic trioxide?

  Realgar is one of several historically confused toxic minerals, and heating turns it into a different, far more dangerous substance. Distinguishing them matters for accurate reference.

  • Realgar (Xiong Huang, 雄黃, “masculine yellow”) — arsenic sulfide, As4S4, orange-to-red in color.
  • Orpiment (Ci Huang, 雌黃, “feminine yellow”) — a related but chemically distinct arsenic sulfide mineral (As2S3), golden-yellow, that commonly co-occurs with realgar in nature and is a separate substance in materia medica.
  • Cinnabar (Zhu Sha) — mercury sulfide (HgS), a different toxic red mineral; historical texts (e.g. Li Shizhen) warn of realgar being adulterated with or substituted for cinnabar due to superficial color similarity.
  • Arsenic trioxide (Pi Shuang, 砒霜) — NOT the same starting material, but the compound realgar becomes when heated/calcined; arsenic trioxide is markedly more water-soluble and acutely toxic than intact As4S4 (see Toxicity).

  Formula context (reference only): realgar appears alongside cinnabar in some classical multi-ingredient formulas, such as An Gong Niu Huang Wan. Animal research on this formula found that the other herbs in the combination measurably reduced the liver and kidney toxicity produced by the cinnabar/realgar minerals alone, though this is preclinical (mouse) evidence, not a safety guarantee for human use. (Traditional formula context, not treatment advice.)

  Source: mineralogical and materia medica references distinguishing realgar/orpiment/cinnabar/arsenic trioxide; PMID 29950994 (An Gong Niu Huang Wan hepatorenal toxicity, mouse study).

This herb is banned or illegal in the United States