Chan Su (Toad Venom, Dried Toad Skin Secretions)

Chinese Herb Actions

Chinese Herb Contraindications & Cautions

• Is Chan Su safe? Are there cautions or contraindications?

  No — Chan Su is a potent cardiotoxin, and it is documented as unsafe outside licensed professional and pharmaceutical contexts. It is contraindicated in pregnancy, and even small excess exposure has been documented to cause life-threatening cardiac arrhythmias. Its use is restricted to standardized, licensed pharmaceutical preparations administered under professional supervision; this entry documents these facts as public-safety reference information, not as usage instructions.

  • Contraindicated in pregnancy — classical and modern sources describe Chan Su as capable of stimulating uterine smooth muscle, and it is listed among substances to be avoided in pregnancy.
  • Fatal poisonings on record — the U.S. CDC documented four deaths among five men in New York City (1993–1995) after use of a topical/oral product marketed as an aphrodisiac that was later found to contain bufadienolides; forensic chemical analysis subsequently showed the West Indian aphrodisiac product “Love Stone,” implicated in a separate fatality, was compositionally near-identical to Chan Su. A published case report describes a fatal ingestion of aphrodisiac pills producing severe bradycardia, hyperkalaemia, acidosis, and cardiac arrhythmia resembling digoxin toxicity.
  • Narrow margin, professional-only use — because its cardioactive compounds act like digitalis, the margin between a traditionally used amount (in licensed, standardized pharmaceutical preparations) and a toxic or fatal exposure is documented as narrow; it is not a substance for self-preparation or self-administration.

  Source: CDC MMWR (PMID 7476839); Heart case report (PMID 12639891); Journal of Forensic Sciences (PMID 8914298); materia medica consensus on pregnancy contraindication. Reference facts on documented risk, not treatment or dosing guidance.

Chinese Herb Toxicity & Overdose

• High — Chan Su is classified as toxic and is a documented potent cardiotoxin. Its bufadienolide compounds (bufalin, cinobufagin, and related steroids) inhibit the cardiac Na⁺/K⁺-ATPase pump in the same manner as digoxin and other cardiac glycosides, and separately suppress cardiac L-type calcium current and the hERG (IKr) potassium current — a dual mechanism shown to make bufadienolides more arrhythmogenic than comparable cardenolides such as digoxin at equivalent pump-inhibition potency.

  Clinically documented consequences include bradycardia, atrioventricular block, hyperkalaemia, and life-threatening ventricular arrhythmia. A retrospective clinical case series of toad-toxin poisoning (36 patients) reported cardiac complications in roughly a third of cases and an overall mortality of about 8%. Because bufadienolides structurally resemble digoxin, poisoning can also produce false-positive results on standard digoxin immunoassays, and digoxin-specific antibody (Fab) fragments have been reported as a treatment for severe poisoning — reference facts describing documented clinical management of poisoning cases, not guidance for use.

  Source: Scientific Reports ion-channel mechanism study (PMID 28550304); CDC MMWR (PMID 7476839); Heart case report (PMID 12639891); Therapeutics and Clinical Risk Management case series (PMID 33363378); Journal of Ethnopharmacology review (PMID 30905791). Reference note on documented toxicity, not a safety guarantee or treatment protocol.

• This herb is considered extremely 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

• Documented interaction risk with cardiac glycosides (e.g., digoxin) and other cardioactive agents. Because Chan Su's bufadienolides act on the same cardiac Na⁺/K⁺-ATPase target as digoxin, co-exposure is expected to compound cardiotoxicity and arrhythmia risk. A separate, clinically relevant point documented in the poisoning literature: bufadienolides cross-react with standard digoxin immunoassays, producing false-positive digoxin readings in patients who have never taken digoxin — a recognized diagnostic pitfall for clinicians evaluating suspected poisoning. These are reference facts for clinician/practitioner awareness, not treatment advice.

  Source: CDC MMWR (PMID 7476839); Heart case report (PMID 12639891); Journal of Forensic Sciences (PMID 8914298).

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 Chan Su (Venenum Bufonis) and its chemistry?

  Yes — Chan Su's active chemistry (bufadienolide cardiotonic steroids) is well characterized, and modern research includes both toxicology and an active oncology research literature, though this is early-stage research context, not a treatment claim.

  • Chemistry — Chan Su/Venenum Bufonis has been shown by chromatographic analysis to contain dozens of distinct bufadienolides (cardiotonic steroid compounds), principally bufalin, cinobufagin, and resibufogenin, together with indole alkaloids; a preparative HPLC method isolated bufalin and cinobufagin from Chan Su at >98% purity for research use.
  • Pharmacology/toxicology review — a 2019 Journal of Ethnopharmacology review of Venenum Bufonis summarizes its traditional use, chemistry (roughly 140 bufadienolides and over a dozen indole alkaloids identified across the literature), and pharmacology (cardiotonic, antinociceptive, anti-inflammatory, antitumor activity in laboratory studies), while explicitly flagging cardiotoxicity, neurotoxicity, and poor bioavailability as obstacles to drug development.
  • Oncology research interest (bufadienolides) — laboratory studies report that bufalin and cinobufagin induce apoptosis (programmed cell death) and cell-cycle arrest across multiple cancer cell lines (including liver, lung, and prostate cancer models) in vitro; a review of a decade of bufalin cancer research describes it as a broad-spectrum candidate still requiring large-scale clinical validation.
  • Early human trial (purified pharmaceutical extract, not raw Chan Su) — a Phase 1 U.S. pilot study of intravenous huachansu (a standardized cinobufacini/toad-venom extract, dose-escalated to levels reported as roughly eightfold typical Chinese clinical dosing) in 15 patients with hepatocellular, non-small-cell lung, or pancreatic cancer found no dose-limiting toxicity and stable disease in six patients (median 6 months); this is a small, uncontrolled early-phase study of a pharmaceutical-grade extract, not evidence supporting use of the raw substance.

  Overall: chemistry and mechanism are well documented; oncology evidence remains preclinical/early-phase, and none of this displaces the substance's well-documented cardiotoxicity risk profile above.

  Sources: PMID 18218193 (bufalin/cinobufagin isolation, J Chromatogr Sci); PMID 30905791 (Venenum Bufonis review, J Ethnopharmacol); PMID 23317181 (bufalin anti-tumor mechanisms review, Asian Pac J Cancer Prev); PMID 19701908 (huachansu Phase 1 pilot study, Cancer); PMID 28550304 (bufadienolide ion-channel mechanism study, Sci Rep). Research context only, not a therapeutic claim.

Chinese Herb Notes

• What is Chan Su made from, and how does it appear in classical formulas?

  Chan Su is the dried white secretion of the parotid (auricular) and skin glands of toads of the genus Bufo — principally Bufo gargarizans and Bufo melanostictus — collected, dried, and processed into cakes or powder as the pharmacopoeial material Venenum Bufonis / Bufonis Venenum.

  Classical formula context (reference only, not usage guidance): Chan Su appears as one component — in minute proportion — of a small number of classical multi-ingredient patent formulas for toxic sore throat and toxic swellings, most notably Liu Shen Wan (“Six Spirit Pill,” alongside Niu Huang/cattle bezoar, Zhen Zhu/pearl, Xiong Huang/realgar, She Xiang/musk, and Bing Pian/borneol). Such formulas are compounded, standardized, and dispensed only as licensed pharmaceutical products; the raw secretion is not used on its own outside professional/pharmaceutical processing.

  Note: the Sacred Lotus records the pharmaceutical Latin name as “Secretio Bufonis.” The wider literature and Chinese Pharmacopoeia most commonly use “Venenum Bufonis” / “Bufonis Venenum.” These refer to the same material (dried toad-gland secretion); the identity field is left unchanged pending owner confirmation.

  Source: Sacred Lotus Sacred Lotus sources & references fields; published materia medica consensus on classical multi-ingredient toxic-throat/sore formulas; Journal of Ethnopharmacology review (below).

This herb is toxic or restricted in the United States