Chang Shan (Dichroa Root)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Chang Shan?

  Reference materia medica sources converge on roughly 5–9 g in decoction (some give a slightly wider 3–10 g range), placing Chang Shan in the same low-gram range as many other potent/toxic herbs rather than the higher ranges used for gentle tonics. This is reference information only, not a usage instruction — Chang Shan is a toxic herb reserved for professional, supervised use.

  Two dosage-related reference points recur across sources:

  • Nausea/vomiting occurs within the ordinary therapeutic range — sources describe strong emesis as an intrinsic effect of the herb, not solely a marker of overdose, and caution against exceeding the stated range.
  • Processing changes the dose-effect/toxicity balance — raw Chang Shan is described as carrying the highest toxicity and strongest emetic effect; dry-fried, wine-processed, or vinegar-processed forms are traditionally used to moderate (not eliminate) the emetic/toxic effect, generally at some cost to potency.

  Source: multiple online sources. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Chang Shan?

  Chang Shan is a toxic herb with real, well-documented cautions: it is contraindicated in pregnancy and is not given to patients of weak or deficient constitution. Multiple materia medica references independently state pregnancy as a firm contraindication, and separately flag Qi deficiency, general constitutional weakness, and elderly or frail patients as populations for whom the herb’s strong emetic action is considered too harsh. Sources are explicit that overdose must be avoided and that use belongs under qualified professional supervision, with a defined dose ceiling rather than open-ended dosing.

  • Pregnancy — contraindicated across sources.
  • Weak/deficient constitution — not given to Qi-deficient, elderly, or otherwise frail patients because of the strength of the emetic response.
  • Risk/benefit framing — because vomiting is an expected effect even at ordinary doses, reference sources frame appropriate use as reserved for situations where the antimalarial (or phlegm-expelling) benefit is judged to outweigh the emetic burden, under professional guidance.

  Source: multiple online sources; toxicology consensus (below).

Chinese Herb Toxicity & Overdose

• Toxic — this site’s own record records Chang Shan’s nature as “Bitter, Spicy, Cold, Toxic,” consistent with the wider TCM and pharmacological literature. Strong nausea and vomiting are described as occurring even at ordinary therapeutic doses, and this is treated as an intrinsic pharmacological effect rather than exclusively a sign of overdose. Modern phytochemical review literature attributes both the antimalarial efficacy and the toxicity to the herb’s quinazolinone alkaloids, principally febrifugine, and reports that raw or excessive use has been associated with adverse effects extending to the liver, kidney, and heart, alongside gastrointestinal effects (nausea, vomiting, abdominal pain, diarrhea). Febrifugine itself has not advanced into stand-alone pharmaceutical use as an antimalarial because of this dose-limiting toxicity, which is why chemical research has focused on lower-toxicity analogs (see research, below) rather than the parent compound. Traditional processing (dry-frying; wine- or vinegar-processing) is used to moderate, but does not eliminate, the toxic/emetic effect. A defined dose ceiling and professional supervision are treated as standard safety practice for this herb.

  Source: 2024 phytochemistry/toxicology review (PMID 38537842, DOI 10.1016/j.jep.2024.118093); Bensky-consistent materia medica references. Reference note, not a 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 well-established clinical herb–drug interaction studies specific to Chang Shan were identified. Given documented preclinical signals of liver, kidney, and cardiac involvement at raw/excessive doses (see toxicity, above), practitioner awareness is reasonable for patients already taking hepatotoxic medications or pharmaceutical antimalarials — this is precautionary, drawn from the toxicity literature, and is not a demonstrated clinical drug interaction. (Flagged for practitioner confirmation.) See also the notes section for an unresolved discrepancy regarding a traditionally cited Gan Cao (licorice) combination caution.

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 Chang Shan (Radix Dichroae) and its febrifugine alkaloid?

  Yes — extensive phytochemical and mechanistic research, mostly preclinical, tracing back to febrifugine’s isolation as Chang Shan’s active antimalarial alkaloid in the mid-20th century. Chang Shan remains a live research subject precisely because it was one of the herbal sources that pointed toward a genuine antimalarial compound, even though that compound was never successfully developed into a clinical drug.

  • Phytochemistry & toxicology review (2024) — a comprehensive review reports roughly 30 isolated compounds (alkaloids, terpenoids, flavonoids, and others) and summarizes reported antimalarial, anti-inflammatory, anti-tumor, and anti-parasitic activities, alongside toxicology findings of liver, kidney, and heart involvement; the authors note that methods proposed to reduce toxicity (structural modification, processing, altered dosage forms) still need further safety validation.
  • Mechanism of action — febrifugine and its synthetic derivative halofuginone have been shown to bind glutamyl-prolyl-tRNA synthetase (EPRS) and inhibit its prolyl-tRNA synthetase activity, activating an amino-acid-response pathway that is proposed to underlie the compound family’s broad bioactivity (antimalarial, anti-inflammatory, immunomodulatory).
  • Malaria-parasite-specific target — the cytoplasmic prolyl-tRNA synthetase of Plasmodium falciparum has been identified as a biochemical and functional target of febrifugine and its analogs, active against both liver-stage and blood-stage parasites in preclinical models — the basis for continued interest in developing safer febrifugine-derived compounds.

  Despite this research interest, febrifugine itself has not become a clinical antimalarial drug because of dose-limiting toxicity (chiefly hepatic); current work centers on synthetic analogs designed to separate the antimalarial mechanism from the toxicity, not on Chang Shan or febrifugine as a stand-alone clinical treatment. Treat all of the above as preclinical/mechanistic research context, not evidence of clinical safety or efficacy.

  Sources: PMID 38537842, DOI 10.1016/j.jep.2024.118093 (phytochemistry/toxicology review, Journal of Ethnopharmacology, 2024); PMID 22327401, PMC 3281520 (EPRS mechanism, Nature Chemical Biology, 2012); PMID 25995223 (parasite-specific PfcPRS target, Science Translational Medicine, 2015). Research context, not a therapeutic claim.

Chinese Herb Notes

• What is Chang Shan traditionally combined with?

  Chang Shan is classically the “king” (chief) herb of Jie Nue Qi Bao Yin (“Seven-Treasure Decoction to Check Malarial Disorders”), paired with Cao Guo (tsaoko fruit) and Bing Lang (areca seed) as deputies to strengthen the antimalarial and phlegm/damp-resolving action, with Hou Po, Qing Pi, and Chen Pi assisting and Gan Cao (licorice) traditionally listed as the envoy herb that harmonizes the formula. (Traditional formula context, not treatment advice.)

  Note: Some modern secondary references caution that combining Chang Shan with Gan Cao intensifies vomiting, yet Gan Cao is a named envoy ingredient in the classical formula Jie Nue Qi Bao Yin above. We could not resolve this discrepancy (possibly a raw-vs-processed-Chang-Shan distinction, or a caution specific to standalone/high-dose use) and have not treated the Gan Cao caution as an established fact pending further sourcing.

  Source: multiple online sources cross-referenced against multiple online sources.

This herb is considered toxic