Ma Qian Zi (Nux Vomica Seeds)

Chinese Herb Actions

Chinese Herb Dosage

• What is the dosage of Ma Qian Zi, and why is processing mandatory?

  Reference literature places the internal dose of processed (sand-fried) Ma Qian Zi powder at only about 0.3–0.6 g per day — a strikingly small ceiling compared with most Chinese herbs, reflecting how close the effective range sits to the toxic range. A Hong Kong case series citing the Chinese Pharmacopoeia (2015) confirms this 0.3–0.6 g/day reference range and reports that overdoses of just 15–31 times that amount produced clinical strychnine poisoning.

  Raw Ma Qian Zi is never used internally. Processing (sand-frying, then grinding to powder) is documented to lower measured strychnine/brucine content in the finished product versus the raw seed. This is reference toxicology information, not a preparation or self-use instruction — internal use is confined to tiny, short-course, professionally supervised doses.

  Source: PMID 35169461, PMC 8817065 (case series citing Chinese Pharmacopoeia 2015 dose range and overdose multiples); PMID 12776527 (HPLC comparison showing lower alkaloid content in processed vs. raw product). Reference range for practitioners only — not a prescription or preparation instruction.

Chinese Herb Contraindications & Cautions

• Are there cautions or contraindications for Ma Qian Zi?

  Ma Qian Zi is strictly contraindicated in pregnancy. Reference sources also advise against its use in general debility/weakness, in children, and in anyone with a cardiac or seizure-prone condition, given strychnine’s excitatory action on the central nervous system. It is used only in its processed (sand-fried) form — raw seeds are not used internally — and only as a small, short-course dose under qualified professional supervision; the reference literature repeatedly cautions against large doses or prolonged use because the effective and toxic ranges sit so close together.

  Source: materia medica consensus on toxic-substance contraindications; PMID 39983805 (narrow therapeutic window, toxicity-mitigation review); PMID 35169461 (documented overdose outcomes). Reference only, not medical advice.

Chinese Herb Toxicity & Overdose

• Is Ma Qian Zi toxic, and what does strychnine poisoning look like?

  Yes — Ma Qian Zi is classified as very toxic. Its two main alkaloids, strychnine and brucine, are both toxic principles, with strychnine reported as substantially more potent than brucine. Strychnine acts as a competitive antagonist at glycine receptors, the central nervous system’s main inhibitory-neurotransmitter site in the spinal cord and brainstem; blocking glycine’s inhibitory signal leaves motor neurons unopposed, producing the muscle spasms and convulsions characteristic of overdose.

  A Hong Kong case series of 12 confirmed strychnine-poisoning patients traced to Ma Qian Zi (overdoses of 15–31× the reference dose) documented muscle spasms (most patients), convulsions with preserved consciousness (notably different from epileptic seizures, which impair awareness), agitation, palpitations, and heightened sensitivity to sound; symptoms began within roughly half an hour and resolved within hours with supportive care (benzodiazepines, activated charcoal), and no deaths occurred in that series. Separately, laboratory research links Semen Strychni and its alkaloids to kidney-cell injury (apoptosis via inflammatory signaling pathways), consistent with organ involvement reported in more severe poisoning.

  Source: PMID 1311851 (glycine-receptor strychnine-binding mechanism); PMID 35169461, PMC 8817065 (Hong Kong strychnine-poisoning case series); PMID 39798900 (Strychni Semen–induced kidney-cell apoptosis, preclinical). Toxicology reference, not a preparation or self-use instruction.

• 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 table of clinical herb–drug interactions is documented for Ma Qian Zi. Given strychnine’s action as a CNS excitatory agent (glycine-receptor antagonism), reference sources support practitioner caution around other drugs or substances that lower seizure threshold or otherwise increase CNS/neuromuscular excitability; this is precautionary, not a demonstrated clinical interaction. Separately, preclinical toxicokinetic research on the classical herb pairing with Gan Cao (licorice) found that co-administration measurably lowered blood and organ levels of strychnine/brucine and sped their clearance from the brain, consistent with a traditional detoxifying rationale for that combination — again preclinical, not a clinical safety guarantee. (Flagged for practitioner confirmation — Ma Qian Zi is used only in processed form, at a very small dose, under qualified supervision.)

  Source: PMID 1311851 (strychnine CNS mechanism); PMID 34984711 (Semen Strychni + Radix Glycyrrhizae toxicokinetic/detoxification study, preclinical). Reference caution, not a medical claim.

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 Ma Qian Zi (Semen Strychni)?

  Yes — a substantial and growing literature, dominated by toxicology and mechanism studies alongside newer efficacy research. Chemically, Ma Qian Zi’s activity and toxicity both trace to its indole alkaloids, chiefly strychnine and brucine.

  • Mechanism / toxicology — strychnine’s convulsant action is explained by competitive antagonism at the glycine receptor, whose strychnine-binding site has been structurally mapped to the receptor’s alpha subunit; a 2025 review summarizes ongoing efforts to reduce toxicity through processing, herb combination, and novel dosage forms, while noting current methods still have limitations.
  • Poisoning case data — a 12-patient Hong Kong case series confirms the narrow real-world margin: doses of 15–31× the 0.3–0.6 g/day reference range produced strychnine poisoning (muscle spasms, “awake” convulsions), with full recovery in every case under supportive care.
  • Myasthenia gravis (preclinical/network pharmacology) — a 2022 network-pharmacology and molecular-docking study, with experimental verification, proposes that Semen Strychni’s alkaloids act on cholinergic-synapse targets relevant to myasthenia gravis; this is hypothesis-generating systems-biology research, not clinical-trial evidence.
  • Organ toxicity — 2025 cell-culture work shows Semen Strychni and its alkaloids trigger kidney-cell (HK-2) apoptosis via inflammatory signaling pathways, and separate toxicokinetic research shows the classical Gan Cao (licorice) pairing lowers alkaloid exposure in blood and organs — preclinical evidence relevant to the herb’s traditional and safety profile.
  • Brucine pharmacology — a 2020 review catalogs brucine’s wider pharmacological activity (anti-tumor, anti-inflammatory, analgesic, cardiovascular and nervous-system effects) alongside the CNS toxicity that limits its clinical use.

  Across this literature, human clinical-trial evidence remains essentially absent; almost all efficacy signals are preclinical (cell/animal/network-pharmacology), while the toxicology and poisoning evidence is comparatively strong and clinical.

  Note: The local database records the pharmaceutical Latin name as “Semen Strychnotis,” while the Chinese Pharmacopoeia and the research literature consistently use “Semen Strychni” / “Strychni Semen.” These refer to the same substance (the dried ripe seed of Strychnos nux-vomica L.); the identity field is left unchanged pending owner confirmation.

  Sources: PMID 1311851 (glycine-receptor mechanism); PMID 39983805, DOI 10.1016/j.jep.2025.119515 (toxicity-mitigation review); PMID 35169461, PMC 8817065 (poisoning case series); PMID 36217431 (myasthenia gravis network pharmacology); PMID 39798900, DOI 10.1016/j.toxicon.2024.108224 (nephrotoxicity mechanism); PMID 34984711 (licorice detoxification toxicokinetics); PMID 32308621 (brucine pharmacology/toxicology review). Research context, not a therapeutic claim.

Chinese Herb Notes

• How does Ma Qian Zi differ from Chuan Wu/Cao Wu and Ru Xiang/Mo Yao?

  Ma Qian Zi sits among the toxic, processed-only substances used for stubborn painful obstruction and traumatic injury, but its profile is distinct from the other main options.

  • vs Chuan Wu / Cao Wu (prepared aconite) — both are very toxic, processed-only herbs used for painful obstruction, but the aconites are acrid and hot, chosen for cold-type bi pain, and dosed in whole grams; Ma Qian Zi is bitter and cold, is favored specifically for numbness/paralysis and unblocking the channels, and its dose ceiling is a small fraction of a gram.
  • vs Ru Xiang / Mo Yao (frankincense/myrrh) — both are traditional choices for traumatic injury with swelling and pain, but Ru Xiang and Mo Yao are resin-based blood-invigorating herbs with a comparatively mild toxicity profile, while Ma Qian Zi is a strychnine-bearing seed with a far narrower, more dangerous margin.
  • vs Quan Xie / Wu Gong (scorpion/centipede) — these toxic-insect medicinals are classically paired with Ma Qian Zi–type substances toward the same target (stubborn wind-damp bi, spasm, paralysis) via a shared channel-unblocking, wind-extinguishing strategy, though they come from an entirely different (animal, not alkaloid-seed) toxicity class.

  Source: materia medica consensus on wind-damp/toxic-substance differentiation. No formulas are currently linked to this herb in the local database, so specific formula names are not cited here.

This herb is toxic or restricted in the United States