Ma Qian Zi
StarStrychnos nux-vomica L.
Traditionally used for
- Nose & throat
- Nerves & recovery
- Pain & joints
- Skin
Cautions & contraindications
- Pregnancy
- Liver conditions
- Kidney conditions
- Seizure disorders
- Toxic — professional use only
☯ TCM Properties
Unblocks the channels and collaterals, d isperses clumps, cools Blood Heat to reduce swelling and a lleviates pain
Traditional Chinese Uses
Ma Qian Zi (Semen Strychni) is the seed of Strychnos nux-vomica, classed among external-application substances. Bitter and cold and considered extremely toxic, it unblocks the channels and collaterals, disperses clumps and nodules, reduces swelling and strongly alleviates pain. It is used for Wind-Damp painful obstruction, numbness and paralysis, and traumatic injury, and applied to yin-type sores, abscesses, scrofula and other stubborn swellings; the processed powder is sometimes blown into the throat for severe sore throat.
The seed contains strychnine and is genuinely poisonous. It must never be used raw internally: it is dry-fried (or processed in oil) and given only as a tiny, carefully measured powdered dose within strict limits, or used topically. Overdose causes convulsions and can be fatal. It is contraindicated in pregnancy and requires close professional supervision.
Relationships
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Botanical Description
Strychnos nux-vomica is a small deciduous tree of the Loganiaceae, native to the dry deciduous forests of India, Sri Lanka, Myanmar, and parts of Southeast Asia, reaching about 10–13 m. The bark is grey and the wood pale, hard, and bitter. Opposite, glossy ovate leaves 5–10 cm long display three to five prominent palmate veins. Small greenish-white tubular flowers appear in terminal cymes, succeeded by orange to scarlet globose berries 4–6 cm across, each containing several flat, disc-shaped grey-velvety seeds about 2 cm in diameter. The seeds are the medicinal organ and the source of the alkaloids strychnine and brucine. The substance is extremely toxic in the raw state; all medicinal preparations across traditions require careful detoxification (oil frying, sand-roasting, or prolonged decoction in milk).
Active Constituents
Strychnine
Monoterpene indole (Strychnos-type) alkaloidConcentration: roughly 1.2-2.1% of the raw seed; the Chinese Pharmacopoeia requires 1.2-2.2% in the processed drug, and sand-frying has been measured to cut it from 1.40% to 0.52%, or by close to 90% when roasting is followed by boiling
The toxic principle and the reason the drug exists as a controlled item. Strychnine is a competitive antagonist at the postsynaptic glycine receptor, a ligand-gated chloride channel, in the spinal cord and brainstem. Blocking glycinergic inhibition leaves motor neurons unopposed, so any stimulus provokes violent generalised muscle contraction, opisthotonos, risus sardonicus and trismus, while the cortex is untouched and the patient stays fully awake and in pain throughout. Death follows from respiratory muscle spasm, hyperthermia, rhabdomyolysis and acidosis. The median lethal dose is on the order of 1.5-2 mg/kg, symptoms begin within 15-30 minutes of ingestion, and the elimination half-life is 10-16 hours.
Brucine
Dimethoxy-substituted Strychnos indole alkaloidConcentration: roughly 1.3-1.4% of the raw seed; the Chinese Pharmacopoeia sets a floor of not less than 0.8% in the processed drug, and sand-frying has been measured to cut it from 1.17% to 0.45%
The alkaloid credited with most of the analgesic and anti-inflammatory action for which the drug is used, and roughly an order of magnitude less convulsant than strychnine, but toxic in its own right and never safely separable from it in a crude preparation. It intercalates DNA and is cytotoxic, and it is cleared by CYP3A, so its toxicity varies with the timing of dosing and with anything that alters that enzyme.
Strychnine N-oxide, brucine N-oxide, isostrychnine and isobrucine
Minor Strychnos indole alkaloids and N-oxidesMinor alkaloids of the seed whose proportions shift markedly during processing; some are generated by heating rather than present in the raw seed. They are analytically useful as processing markers and contribute little to the pharmacology.
Loganin
Iridoid glycosideA non-alkaloidal seed constituent, biosynthetically the precursor of the monoterpene half of the indole alkaloids. It has no meaningful part in either the therapeutic or the toxic action of the drug.
⚠ Drug Interactions
Fan Mu Bie (the same drug, Semen Strychni), and Ma Qian Zi Fen or any patent medicine containing it
Fan Mu Bie is not a different drug. It is one of the older Chinese names for the seed of Strychnos nux-vomica, recorded alongside Ku Shi and Qian Ji Yao, and the name Ma Qian Zi and the name Fan Mu Bie were first brought together in the Ben Cao Gang Mu. The fan-mu-bie record in this corpus carries the identical binomial and the identical latin name Semen Strychni, so the two records describe one drug under two names. With most herbs a duplicate entry is a tidiness problem. Here the therapeutic dose is a few tenths of a gram and the convulsant dose is not far above it, so a formula that contains both names, or a patient taking a patent pill plus a prescribed powder, can double an exposure that has no headroom.
Clinical note: Treat Ma Qian Zi, Fan Mu Bie, Ma Qian Zi Fen and Semen Strychni as one item and add the doses. Never dispense a formula listing both.
CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin, ritonavir, grapefruit juice)
Both principal alkaloids are cleared by CYP3A. Brucine toxicity in mice tracks the diurnal rhythm of Cyp3a11, the mouse orthologue of human CYP3A4, and mice with lower Cyp3a11 activity show greater brucine toxicity; human CYP3A4 is a major contributor to brucine metabolism. In vitro work in human liver microsomes likewise identifies CYP3A4 as the main enzyme metabolising strychnine. Since a dose increment of a tenth of a gram is enough to provoke the nux vomica response clinically, any inhibitor that raises plasma alkaloid by even a modest factor moves a therapeutic dose into the toxic range.
Clinical note: Do not prescribe Semen Strychni to a patient on a moderate or strong CYP3A4 inhibitor. Ask specifically about azole antifungals, macrolides, HIV protease inhibitors and grapefruit.
Gan Cao (Glycyrrhiza uralensis) and glycyrrhetinic acid
Licorice is the classical partner used to moderate Semen Strychni, and the pairing turns out to have a measurable enzymatic basis. In rats given brucine for seven days, brucine alone cut CYP3A-associated testosterone 6-beta-hydroxylation by 24.5% and CYP2C-associated tolbutamide hydroxylation by 34.6% while raising CYP2E1 activity by 146.1%; adding glycyrrhetinic acid brought CYP2E1 and CYP1A2 activity back down by 51.4% and 33.5%, and liquiritin antagonised the CYP2E1 rise. The authors read this as part of how Gan Cao detoxifies nux vomica. The other side of the same coin is that glycyrrhetic acid competitively inhibits strychnine metabolism in human liver microsomes, so co-administration is also capable of raising strychnine exposure.
Clinical note: Do not treat Gan Cao as a licence to raise the Semen Strychni dose. Keep the dose where it would be without it, and if licorice is added or withdrawn mid-course, re-titrate rather than assuming the previous dose is still equivalent.
Other strychnine exposures: strychnine rodenticide, strychnine-adulterated illicit drugs
Rodenticide and adulterated street heroin are the classical sources of strychnine poisoning, and Semen Strychni is a third, unusual one. All three deliver the same molecule to the same glycine receptor, so exposures add with no threshold effect to protect the patient. In the Hong Kong laboratory series covering 2005 to 2018, Strychni semen was the exclusive source in all twelve confirmed cases, and three of the twelve poisoned patients were themselves TCM practitioners.
Clinical note: Take a drug-use and occupational history before prescribing. Conversely, in a patient presenting with conscious convulsions, ask about Chinese herbal medicine as well as about rodenticide and heroin, because that history is what makes the diagnosis quickly.
Agents that lower the seizure threshold or raise motor excitability (tramadol, bupropion, theophylline, high-dose fluoroquinolones, stimulants)
Strychnine's convulsions are spinal and brainstem in origin rather than cortical, so they are not seizures in the epileptic sense, but the toxic endpoint is still unopposed motor excitation and it is reached by summation. Any co-administered agent that increases central excitability moves the patient closer to that endpoint from the other direction. There are no controlled data, because such a study could not be done ethically.
Clinical note: Avoid the combination. Also avoid in patients with a seizure disorder, and warn patients that the muscle twitching and stiffness that mark the nux vomica response are the signal to stop the drug, not to push through.
Nephrotoxic drugs (NSAIDs, aminoglycosides, contrast media)
Semen Strychni is directly toxic to renal tubular cells: in HK-2 human proximal tubule cells, the crude drug and both isolated alkaloids activated TRADD-mediated JNK and p38 MAPK and NF-kB signalling, upregulated caspase-3, raised IL-6, IL-1 beta, TNF-alpha and the injury marker KIM-1, and drove apoptosis, all of which was antagonised by the TRADD inhibitor Apostatin-1. On top of that direct injury, the rhabdomyolysis produced by sustained convulsion is itself a cause of acute kidney injury.
Clinical note: Check renal function before and during a course. Avoid in existing renal impairment and alongside other nephrotoxic agents, and stop at once if myalgia or dark urine appears.
Raw (unprocessed) Semen Strychni supplied in place of the processed drug
Only processed seed is used. Sand-frying until the seeds crack and brown reduces measured strychnine from 1.40% to 0.52% and brucine from 1.17% to 0.45%; roasting in sand followed by boiling in water has been reported to cut strychnine by around 90% against the crude seed. Li Shizhen's tofu-steaming method in the Ben Cao Gang Mu is the classical version of the same operation. A dose calculated for the processed drug and dispensed as raw seed therefore carries several times the intended alkaloid load, and this record describes the processed drug.
Clinical note: Dispense only pharmacopoeial processed seed with a certificate of alkaloid assay, and never carry a dose across from one processing method to another. The Pharmacopoeia both caps and floors the alkaloid content, so an out-of-specification batch is unusable in either direction.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| powder | 0.3–0.6 g | — | — | — | ChP 2025. 炮制后入丸散用 — processed, in pills or powder only. Contraindicated in pregnancy; not to be taken in large amounts or over a long period, and not used raw; caution in athletes (strychnine is a prohibited substance). Toxic constituents are absorbed through skin — do not apply externally over a large area. Corrected from a generic 'As needed' poultice filler value generated from tcm_category. |
Evidence Tier
Moderate evidence · 7 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
1
1 verified · 0 unverified
Other clinical trial
0
Observational / case report
1
1 verified · 0 unverified
In vitro / animal
5
1 verified · 4 unverified
Show 5 studies
- Strychni Semen and two alkaloidal components cause apoptosis in HK-2 cells through TRADD-MAPK/NF-κB pathway
- Cyp3a11 metabolism-based chronotoxicity of brucine in mice
- Effects of brucine combined with glycyrrhetinic acid or liquiritin on rat hepatic cytochrome P450 activities in vivo
- Cytotoxicity and DNA interaction of brucine and strychnine—Two alkaloids of semen strychni
- Pharmacokinetics-Based Chronoefficacy of Semen Strychni and Tripterygium Glycoside Tablet Against Rheumatoid Arthritis
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
Strychnine poisoning due to traditional Chinese medicine: a case series
Review of every strychnine poisoning confirmed by Hong Kong's Hospital Authority Toxicology Reference Laboratory between May 2005 and May 2018. Twelve cases were found and Strychni semen was the exclusive source in all of them. Ten patients (83%) had muscle spasms and four (33%) developed typical conscious convulsions; poisoning was severe in two, moderate in three and mild in eight. Three patients were TCM practitioners and two were laypeople who had bought the herb without a prescription. There were no deaths in this series, but the authors stress that the clinical picture is indistinguishable from rodenticide or heroin-adulterant poisoning and that the herbal history is what makes the diagnosis.
Safety of Individual Medication of Ma Qian Zi (Semen Strychni) Based upon Assessment of Therapeutic Effects of Guo's Therapy Against Moderate Fluorosis of Bone
One hundred and fourteen patients with moderate skeletal fluorosis were block-randomised to Guo's Ma Qian decoction (n = 60) or placebo decoction (n = 54). Semen Strychni was started at 0.4 g and raised by 0.05 g every two days until the patient showed the nux vomica response, to a ceiling of 1.2 g per day. HPLC assay showed 2.125% strychnine and 1.425% brucine before processing and 1.88% and 1.31% after, within the Pharmacopoeia range of 1.2-2.2% strychnine and not less than 0.8% brucine; at the 1.2 g ceiling the decoction delivered 11.17 mg strychnine and 7.44 mg brucine, within the pharmacopoeial cap of 13.32 mg. Eight patients in the treatment arm and one on placebo showed the nux vomica response. The study is the clearest published illustration of how narrow the usable range is: the whole titration spans well under a gram per day.
Strychni Semen and two alkaloidal components cause apoptosis in HK-2 cells through TRADD-MAPK/NF-κB pathway
Strychni Semen extract (10 mg/mL), brucine (8 micrograms/mL) and strychnine (4 micrograms/mL) each activated JNK and p38 within the MAPK and NF-kB pathways in HK-2 human proximal tubular cells, upregulated caspase-3 and drove apoptosis, with increased IL-6, IL-1 beta, TNF-alpha and KIM-1. The TRADD inhibitor Apostatin-1 blocked both the apoptosis and the cytokine rise, identifying TRADD as the upstream node. Direct evidence that the drug is nephrotoxic independently of convulsion-induced rhabdomyolysis.
Cyp3a11 metabolism-based chronotoxicity of brucine in mice
Brucine toxicity in mice varied with dosing time, and the variation tracked the circadian rhythm of hepatic Cyp3a11, the mouse orthologue of human CYP3A4. Lower Cyp3a11 activity meant slower brucine clearance and greater toxicity. The direct implication for practice is that anything perturbing CYP3A4, including co-prescribed drugs, perturbs the safety margin of a drug that has almost none.
Effects of brucine combined with glycyrrhetinic acid or liquiritin on rat hepatic cytochrome P450 activities in vivo
Wistar rats received brucine at 3, 15 and 60 mg/kg/day for seven days, with the high dose given alone or with glycyrrhetinic acid 25 mg/kg/day or liquiritin 20 mg/kg/day. High-dose brucine alone cut CYP3A-associated testosterone 6-beta-hydroxylation by 24.5% and CYP2C-associated tolbutamide hydroxylation by 34.6% and raised CYP2E1-associated para-nitrophenol hydroxylation by 146.1%. Glycyrrhetinic acid reduced CYP2E1 and CYP1A2 activity by 51.4% and 33.5% relative to brucine alone, and liquiritin cut CYP2E1 activity by 41.1% and raised CYP2C activity by 37.7%. The authors interpret this as a mechanistic basis for the traditional use of Gan Cao to detoxify Semen Strychni.
Cytotoxicity and DNA interaction of brucine and strychnine—Two alkaloids of semen strychni
Comparative study of the two alkaloids' cytotoxicity and their binding to DNA, characterising the interaction and relating it to the observed cell toxicity. Relevant to the antitumour claims made for brucine and to the general cytotoxic background against which the drug's neurotoxicity sits.
Pharmacokinetics-Based Chronoefficacy of Semen Strychni and Tripterygium Glycoside Tablet Against Rheumatoid Arthritis
In a rodent arthritis model, the anti-arthritic effect of Semen Strychni varied with dosing time in a way that followed the pharmacokinetics of its alkaloids. Combined with the Cyp3a11 chronotoxicity data, this indicates that both the efficacy and the toxicity of the drug shift across the day, which is a further reason the usable dose cannot be treated as a fixed number.
⚠ Safety & Contraindications
- Pregnancy
- Liver conditions
- Kidney conditions
- Seizure disorders
- Toxic — professional use only
Contraindications
Contraindicated in pregnancy, in the weak or depleted, and in patients with liver or kidney impairment.
Safety Warnings
- Used only after processing (sand-frying or oil-frying) and only at the very small doses stated in the Pharmacopoeia.
- Cumulative — not for prolonged use.
- Strychnine poisoning is a medical emergency.
⚠ 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.
Pregnancy
Avoid toxic (strychnine)
Breastfeeding
Avoid strychnine — toxic to infant
Continuous use
No published day limit; prolonged use cautioned — “不宜多服久服及生用 — not to be taken in large amounts, over a long period, or unprocessed”
孕妇禁用；运动员慎用 — contraindicated in pregnancy; caution for athletes. ChP dose 0.3–0.6 g, processed, in pills or powders. Source: 《中华人民共和国药典》2020年版一部 — 马钱子 【注意】(p. 52). Pending clinical review.
A patient's own days on this herb are counted on their patient page (practitioners only).
⚠ Toxicity Information
Muscular stiffness and twitching, then tetanic convulsions with opisthotonus, triggered by minor sensory stimuli, and death from respiratory muscle spasm. The lethal dose of strychnine is small and the therapeutic margin correspondingly narrow.
Historical Texts
Ben Cao Gang Mu
Ming dynastyChinese Pharmacopoeia (Zhonghua Renmin Gongheguo Yaodian)
Modern, 2015 and 2020 editionsReferences
- Pei Z, Cao Y, Qi X, Li J, Tian J, Zhang Q, Liu L, Cai X, Wu P. Enhancing efficacy and mitigating toxicity of Semen Strychni: From traditional practices to modern pharmaceutical innovations . Journal of Ethnopharmacology (2025) [DOI]
- Yang Y, Yang B. Maqianzi (马钱子Strychnos), A Poisonous Medicinal Native to the Western Regions . Chinese Medicine and Culture (2019) [DOI]
- Cai H. Comparison on in vivo pharmacokinetics of brucine, total alkaloids of Strychni Semen and Strychni Semen pulveratum in rats . China Journal of Chinese Materia Medica (2012) [DOI]
- National Institute of Diabetes and Digestive and Kidney Diseases. Nux vomica . Vademecum Anthroposophische Arzneimittel (2024) [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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