Nux Vomica (Ma Qian Zi)

Semen StrychniThanks to its amazing healing power on activating collaterals and relieving pain, clinically nux vomica, or Ma Qian Zi in pinyin, is often used in TCM (traditional Chinese medicine) for the treatment of trauma, ulcer, rheumatoid arthritis, paralysis, post-polio syndrome, etc. The written record of this herb was first found in the Ben Cao Gang Mu (Compendium of Materia Medica), the most comprehensive herbalism writings in the history of ancient Chinese medicine. It is considered dangerous since the working nux vomica dose is quite close to its minimum toxic dose. So to speak, it is just like a fiery horse with the speed of light, but apparently harnessing it does need a lot of skills and patient even though it is usually castrated (processed) before the use. For the same reason, many herbalists are afraid to use it since using it is just like treading on eggs or walking a tightrope. Toxic reaction will just occur instantly once used it improperly. So, a good understanding about it could go a long way in preventing medical errors.

What is nux vomica?

Medicinally it mainly refers to the mature seeds of Strychnos nux-vomica, which is a plant in the family Loganiaceae. So, other names include poison nut, Nux-Vomica Seeds, Semen Strychni, strychni semen, Quaker buttons, Strychnos Seed, Semen Strychni Nux-vomicae, and so on. The former one is mainly cultivated or uncultivated in India, Vietnam, Myanmar, Thailand and other places. It is usually harvested in winter when the fruits are ripe. After then it needs to remove the flesh, take the seeds, dry in the sun, and process in order to reduce toxic.

Nux vomica plant is a tree, 10 to 13 meters in height. Gray bark is with lenticels. Branches are smooth. Leaves are opposite; petiole length is from 5 to 12mm; leaf blade is leathery, smooth, hairless, broad ovate or oblong, 6 to 15cm long, 3 to 9cm wide, and with acute or slightly concave apex, broad cuneate or rounded base, and entire margin; leaf axils are with short tendrils. Conical cymes are axillary, pubescent, 3 to 5cm, and 2.5 to 5cm in diameter; both bracts and bracteoles are small, triangular, pubescent, and with acute apex; flowers are white and almost sessile; calyx is green, 5-lobed at the tip, and densely pubescent; corolla is tubular and with 5 lobed apex. The lobes are ovate and densely pubescent inside; stamens are 5; pistil is 9.5 to 12mm in length. Berry is spherical, 2 to 4cm in diameter, green when young and orange when ripe, and with smooth surface. Seeds are 1 to 4, disc-shaped, 1 to 3cm in diameter, and with greyish yellow surface that is densely covered with silvery hair. Flowering time is in spring and summer and fruit season is from August to following January.

Seeds contain 2 to 5% total alkaloids, which mainly include 1 to 1.4% strychnine, 1 to 1.4% brucine, a small amount of vomicine, pseudo-strychnine, pseudo-brucine, novacine (N-methyl-sec-pseudobrucine), α, β-colubrine, struxine, loganin or loganoside, about 3% fatty oil, 11% protein, chlorogenic acid, and so on.

Nux vomica benefits

As previously mentioned, this poisonous herb can be also a good medicine for some life-threatening illnesses. (1) The plaster, composed of semen strychni 1g, camphor powder 0.3g, and white wax 4g, can be used for the facial paralysis treatment. The common usage is to paste it on the nerve trunk area in front of the ear lobe in affected side, once every 4 days. Among the 100 cases, 98 cases were cured, and 2 cases were improved after 4 to 32 days of treatment. (2). After treated with Feng Tong San, made of equivalent semen strychni and Ma Huang (Ephedra), the relief was provided in 35 out of 58 cases of chronic rheumatic arthritis, 9 out of 16 cases of chronic rheumatoid arthritis, 3 out of 5 cases of chronic hypertrophic arthritis, and 13 out of 24 cases of general joint pain. (3). 100 cases of neurodermatitis were cured by the preparation of soaking semen strychni 3g and Mi Tuo Seng (lithargite) 3g in 200ml saponated cresol solution. (4). This herb can be also used for the treatment of tinea pedis and manuum (dermatophyte infections of the hands and feet), trigeminal neuralgia, myasthenia gravis, respiratory muscle paralysis, chronic bronchitis, schizophrenia, epilepsy, shoulder periarthritis, and so on.

Modern pharmacological actions of strychni semen

1. Strychnine contained excites the spinal cord’s reflection function, stimulates medulla’s respiratory center and vasomotor center, and improves the cerebral cortex’s sensorium function;
2. Brucine has significant analgesic, antitussive, and expectorant effects. In addition, it has better antitussive and expectorant effect than codeine. But its effect of anti-asthma is relatively weaker;
3. Its decoction has different degrees of inhibition on haemophilus influenzae, Streptococcus pneumoniae, Group A Streptococcus, neisseria catarrhalis bacteria, Trichophyton schoenleinii, etc.

Selected strychnos seed recipes on herbal remedies

According to Chinese Pharmacopoeia, it is bitter in flavor and warm and extremely poisonous in nature. It goes to meridians of liver and spleen. Basic functions are activating meridians to stop pain and removing stasis to reduce swelling. Fundamental nux vomica uses and indications include rheumatism and obstinate arthralgia, numbness, paralysis, traumatic injury, ulcer and swelling, post-polio syndrome, and rheumatoid arthritis joint pain. Recommended dosage is from 0.3 to 0.6 grams in pills or power. Attention please, before the use it should be processed to reduce the toxicity. Generally the strychnine and brucine content can be significantly reduced by stir-baking in sand, frying in oil, boiling along with licorice, and other heating methods.

1. Jiu Fen San from Ji Jiu Ying Yan Liang Fang (Confirmed Effective Prescription for Emergency). It is combined with Ma Huang (Ephedra), Ru Xiang (Frankincense), and Mo Yao (Myrrh) for trauma, fracture, swelling and pain.

2. Ma Qian San from Jiu Sheng Ku Hai (Saving Lives from Abyss of Misery). It is equipped with Shan Zhi Ma (Narrowleaf Screwtree Root), Frankincense, and Chuan Shan Jia (Pangolin Scales) for the treatment of initial period of ulcer, external and internal injuries, and wandering arthritis.

3. Fan Mu Bie San from Yi Fang Zhai Yao (The Summary of Medical Prescriptions). It is formulated with Qing Mu Xiang (Radix Aristolochiae), Shan Dou Gen (Radix Sophorae Tonkinensis), etc., to cure carbuncle and sore throat.

4. Qing Long Wan from Wai Ke Quan Xin Ji (The Surgery Anthology for Carrying the Torch). It is used with Jiang Can (Bombyx Mori) and Zhi Jia Pian (Roasted Pangolin Scales) to treat malignant boil, suppurative osteomyelitis, scrofula, acute mastitis, and phlegm-qi lumps.

Nux vomica side effects

Strychnine can cause poisoning by the dose of 5 to 10mg and death by 30mg. Cause of death is the failure and suffocation due to repeated episodes of tonic convulsions. The main clinical manifestation of nux vomica poisoning include dry mouth, dizziness, headache, gastrointestinal irritation, palpitation, loss of control of the limb, fear, and epileptic seizures. Therefore, the dried medicinal herb, overdose and long-term use are inadvisable. Besides, it shouldn’t be used in pregnant women and weak people.


(1). Jiang Su Zhong Yi (Jiangsu Chinese Medicine), 1988; (6):31.
(2). Xin Yi Xue (New Medicine), 1985; 16 (2):35.
(3). Hu Bei Wei Sheng (Hubei Health); 1977, (7):43.

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