Traditionally used for
- Skin
Cautions & contraindications
- Toxic — professional use only
☯ TCM Properties
Discharges pus and removes putridity topically
Traditional Chinese Uses
Sheng Yao ("ascending medicine") is a processed mineral preparation of mercury compounds, principally red mercuric oxide (HgO), produced by subliming mercury with niter and alum; the red form is Hong Sheng and the yellow Huang Sheng. Pungent and hot, it is a strictly external agent in traditional external medicine (surgery), where it is the classic drug to discharge pus and remove putridity (necrotic tissue): a minute amount is dusted onto, or set on paper wicks inserted into, chronic non-healing ulcers, sinuses, and abscess cavities to clean them so healthy granulation can form. It has also been applied to stubborn eczema, impetigo, and tinea.
Because it is a strongly toxic mercury salt, it is never taken internally and is used only in tiny amounts, almost always blended with calcined gypsum (Shi Gao) and wound-healing herbs to moderate its action. Mercury preparations are toxic and heavily restricted; this is historical practice, described here for reference and not endorsed for self-use.
Relationships
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Botanical Description
Sheng Yao (升药), literally "ascending medicine," is a traditional Chinese mineral-medicinal preparation, not a plant. It comprises crystalline mercury compounds — principally red mercuric oxide (HgO) in the form known as Hong Sheng Dan, or yellow mercuric oxide (Huang Sheng Dan) — produced by sublimation from a charge of mercury, alum, and nitre (potassium nitrate) heated in a closed vessel. The resulting needle-like red or orange-yellow crystals were historically scraped from the lid of the reaction crucible and used externally on chronic ulcers, fistulae, and suppurative skin lesions to debride necrotic tissue. Because mercuric oxides are acutely toxic and dermally absorbed, modern Chinese pharmacopoeial use is highly restricted to external application in trace amounts; the substance is omitted from many modern formularies on safety grounds.
Active Constituents
Mercury(II) oxide (HgO)
Inorganic mercury(II) compound (metal oxide)Concentration: The pharmacopoeial drug Hong Fen (Hydrargyri Oxydum Rubrum) is assayed at not less than 99.0% HgO
This is the entire drug, and it is an inorganic mercury salt, not a plant constituent. In contact with tissue fluid and wound exudate the oxide liberates Hg2+, which binds avidly to sulfhydryl groups on proteins and enzymes. That is simultaneously the intended action, protein precipitation and enzyme inactivation in necrotic tissue and in bacteria, and the toxic action, because the same thiol binding destroys renal tubular epithelium once mercury is absorbed. On ingestion it is corrosive, producing haemorrhagic gastritis and acute tubular necrosis. Mercury absorbed from it accumulates chiefly in the kidney and is eliminated over months, not days.
Residual soluble mercury salts and unreacted mercury from the sublimation process
Process residuesConcentration: Variable and dependent on the quality of the sublimation; not routinely assayed in non-pharmacopoeial material
Sheng Yao is manufactured by subliming metallic mercury with saltpetre and alum, so batches of uncertain provenance can carry soluble mercury salts and unreacted mercury in addition to the oxide. Soluble mercury salts are considerably more readily absorbed than the oxide, so poor-quality material is not merely less effective but more dangerous.
⚠ Drug Interactions
Qing Fen (Calomelas, mercurous chloride Hg2Cl2)
This record has been flagged as possibly carrying the wrong identity, and the flag should be resolved in favour of the oxide. Sheng Yao, also called Hong Fen, Hong Sheng Dan, Huang Sheng, Ling Yao and San Xian Dan, is mercury(II) oxide, HgO, prepared by subliming mercury with saltpetre and alum; the Latin name on this record, Crudum Hydragyrum Oxydatum, agrees. Calomel is a different drug: Qing Fen, Calomelas, mercurous chloride Hg2Cl2, acrid and cold, historically taken internally as well as applied topically. Sheng Yao is acrid and hot, graded as gravely toxic, and is external use only, never internal. A third name compounds the confusion: the parenthetical mercury sublimate on this record properly denotes corrosive sublimate, mercuric chloride HgCl2, which is the Chinese drug Bai Jiang Dan, again a different substance. Treating these three as interchangeable is a documented route to poisoning.
Clinical note: Read this record as mercury(II) oxide, HgO. The parenthetical mercury sublimate in the scientific name is wrong and should be corrected, because it names mercuric chloride. Never accept calomel as a substitute for Sheng Yao or the reverse, and never allow the external-only rule of Sheng Yao to be relaxed on the basis of calomel's historical internal use.
Bai Jiang Dan and mercuric chloride (corrosive sublimate, HgCl2)
Bai Jiang Dan is the descending sublimate counterpart of Sheng Yao and is chiefly mercuric chloride. Because it is water-soluble it is absorbed through broken skin far more efficiently than the oxide. Animal work on external Bai Jiang Dan shows mercuric chloride absorbed into blood and accumulating in the kidney, generating free radicals in tubular cell membranes and producing tubular necrosis. The two drugs are dispensed as similar-looking powders and are sometimes conflated in translation because both are called sublimates.
Clinical note: Verify which sublimate has actually been dispensed before any external mercurial is applied. Do not use two mercurial preparations concurrently on the same patient under any circumstances.
Other mercury- and arsenic-containing materia medica (Zhu Sha/cinnabar HgS, Qing Fen, Xiong Huang/realgar, Pi Shuang/arsenic trioxide)
Mercury from topical Sheng Yao is absorbed, deposits chiefly in the kidney, and is cleared slowly. Rabbit work on the compounded preparation Jiuyi Dan showed blood mercury still significantly elevated 40 days after the drug was stopped, with urine mercury not normalising for around three months. Any concurrent mercurial or arsenical, whether in a patent medicine such as Angong Niuhuang Wan or as a separately dispensed mineral, adds to the same renal burden. Chinese regulators have progressively restricted such preparations for this reason.
Clinical note: Take a full inventory of patent medicines before using any external mercurial, since cinnabar and realgar are common and often unlabelled constituents. Do not stack exposures, and treat cumulative rather than single-dose exposure as the relevant safety metric.
Nephrotoxic drugs (aminoglycosides, NSAIDs, ciclosporin, tacrolimus, cisplatin, tenofovir, amphotericin B, iodinated contrast)
Mercury's target organ is the renal tubule. Rat studies of an external mercury-containing Chinese preparation showed rising urinary retinol binding protein, N-acetyl-beta-D-glucosaminidase and clusterin, together with tubular pathology, at doses that left serum creatinine and urea entirely normal. In other words, mercurial tubular injury is well established before any routine renal test detects it. Adding a second tubular toxin to a kidney already carrying a mercury load has no plausible safety margin, and NSAIDs additionally impair the compensatory renal blood flow response.
Clinical note: Do not apply a mercurial to a patient receiving any of these drugs. If exposure has already occurred, standard creatinine and urea are not adequate monitoring; urinary tubular markers or blood and urine mercury are needed.
Chelating agents (succimer/DMSA, unithiol/DMPS, dimercaprol/BAL, penicillamine)
Dithiol chelators compete with tissue thiol groups for Hg2+ and increase urinary mercury elimination. This is treatment for absorbed mercury, not a prophylactic measure, and chelation of inorganic mercury can redistribute metal transiently. Note also that mercury already bound in renal tubular tissue is far less accessible to chelation than circulating mercury.
Clinical note: If mercury poisoning is suspected, stop the preparation immediately and refer to clinical toxicology. Do not begin chelation empirically, and do not treat the availability of chelation as making continued mercurial use acceptable.
Iodide-containing drugs and herbs (potassium iodide, povidone-iodine antiseptics, Hai Zao, Kun Bu)
Mercury(II) oxide reacts with iodide to form mercuric iodide, itself a highly toxic mercurial with different solubility and tissue behaviour from the parent oxide. There are no clinical studies of this pairing on a wound bed, so this is flagged as chemically predicted rather than clinically demonstrated. The general principle that mercurials should not be combined with other reactive topical antiseptics is long-standing.
Clinical note: Do not apply iodine-based antiseptics to a wound dressed with a mercurial, and do not compound the two. If a wound has been dressed with povidone-iodine, cleanse it before any other agent is considered.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| topical | Appropriate amount | — | — | — | ChP 2025. 本品有毒，只可外用，不可内服 — TOXIC, EXTERNAL USE ONLY, must NOT be taken internally. Ground to an extremely fine powder, alone or compounded into powders or medicated threads. Not for prolonged external use. Contraindicated in pregnancy. Corrected from a generic 'As needed' poultice filler value generated from tcm_category. |
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
0
In vitro / animal
4
0 verified · 4 unverified
Show 4 studies
- Study on different doses of mercury-containing preparations on acute toxicity in rabbits
- Effects of external use of Jiuyi Dan for one month on blood and urine mercury levels and liver and kidney functions of rabbits
- Comparison of effects of Badu Shengji San on rats with different injured skins
- Comparative study on external use of mercury-containing preparation Badu Shengji San in sensitive monitoring indicators of induced early renal injury
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
Study on different doses of mercury-containing preparations on acute toxicity in rabbits
This is the most directly relevant toxicology for this record, because it applied Sheng Dan itself, the red mercuric oxide preparation, topically to wounds. Rabbits received 270 mg calcined gypsum, 300 mg Jiuyi Dan (calcined gypsum to Sheng Dan 9:1), 90 mg Sheng Dan or 180 mg Sheng Dan on 5 cm by 5 cm wounds on the back for five hours, after which the wounds were washed. Both Sheng Dan groups showed significantly raised creatinine at 24 and 72 hours, raised urea nitrogen at 24 hours and day 7, and raised AST at 24 and 72 hours. Blood mercury rose significantly from 24 to 72 hours in all treated groups with a clear dose-effect relationship, and liver and kidney pathological changes were found in both Sheng Dan groups at 14 days. The heavily diluted Jiuyi Dan produced no significant organ effect on a single application, but still raised blood mercury. A single five-hour topical application of the undiluted drug was therefore enough to injure liver and kidney in a healthy animal.
Effects of external use of Jiuyi Dan for one month on blood and urine mercury levels and liver and kidney functions of rabbits
Rabbits had 40 mg of Jiuyi Dan, the 9:1 gypsum to Sheng Dan dilution, applied to a 5 cm by 5 cm back wound for four hours, repeated over one month. Blood mercury was significantly raised at 14 and 28 days and remained significantly raised 7 and 40 days after the drug was stopped; urine mercury was still significantly raised 71 days after withdrawal. Blood mercury took about 71 days and urine mercury about three months to return to baseline. Liver and kidney function indices did not change at this dose. The finding that matters clinically is the kinetics: even the most dilute standard mercurial dressing, at double dose for a month, produces measurable systemic mercury that takes months to clear. Topical here does not mean local.
Comparison of effects of Badu Shengji San on rats with different injured skins
A mercury-containing external Chinese preparation was applied to rats with either abraded skin or ulcerated skin. At the same dose, the ulcerated-skin groups showed markedly higher urinary retinol binding protein and kidney coefficients, clear pathomorphological change in the renal tubules and notable epithelial cytopathic effects compared with the abraded-skin groups. Renal toxicity was distinctly greater through ulcerated skin. This is the central safety point for Sheng Yao, because the drug's whole indication is deep, necrotic, ulcerated and fistulous lesions, which is precisely the surface through which mercury is most efficiently absorbed. The classical indication and the maximal absorption condition are the same condition.
Comparative study on external use of mercury-containing preparation Badu Shengji San in sensitive monitoring indicators of induced early renal injury
Rats given an external mercury-containing preparation at 60 and 120 mg/kg showed no detectable difference in serum creatinine or blood urea nitrogen even while kidney coefficients rose markedly and clear renal tubular pathology was present, with significant rises in urinary clusterin, N-acetyl-beta-D-glucosaminidase and retinol binding protein. At 30 mg/kg, retinol binding protein was already markedly raised with no morphological change yet visible. Sensitivity ranked retinol binding protein above N-acetyl-beta-D-glucosaminidase above clusterin, all ahead of creatinine and urea. The practical conclusion is blunt: normal routine renal function tests do not exclude mercurial nephrotoxicity.
⚠ Safety & Contraindications
- Toxic — professional use only
Contraindications
Don’t take orally and use overdose or continually. It is not suitable for patients with decaying flesh of external ulcers rotting away or ichor draining away.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 412–415.
⚠ Rule-Based Cautions
These entries come from the deterministic rule tables that gate Verscienta's formula tools — classical pair prohibitions, pregnancy and lactation contraindications, and dose ceilings.
Continuous use
No published day limit; prolonged use cautioned — “本品有毒，只可外用，不可内服；外用亦不宜久用 — toxic; external use only, never internal, and not for long even externally”
孕妇禁用 — contraindicated in pregnancy. Source: 《中华人民共和国药典》2020年版一部 — 红粉 【注意】(p. 161). Pending clinical review.
A patient's own days on this herb are counted on their patient page (practitioners only).
Historical Texts
Wai Ke Da Cheng
Qing dynasty (1665)Standing classical caution on Hong Fen and Sheng Yao
Qing dynasty to the present Chinese PharmacopoeiaReferences
- Zhao M, Li Y, Wang Z. Mercury and Mercury-Containing Preparations: History of Use, Clinical Applications, Pharmacology, Toxicology, and Pharmacokinetics in Traditional Chinese Medicine . Frontiers in Pharmacology (2022) [DOI]
- Chan TYK, Chan APL, Tang HL. Nephrotic syndrome caused by exposures to skin-lightening cosmetic products containing inorganic mercury . Clinical Toxicology (2019) [DOI]
- Oliveira DBG, Foster G, Savill J, Syme PD, Taylor A. Membranous nephropathy caused by mercury-containing skin lightening cream . Postgraduate Medical Journal (1987) [DOI]
- Yanli L. Study on mercury accumulation in rats induced by Badu Shengji San . China Journal of Chinese Materia Medica (2012) [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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