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Strychnos Nux-vomica

Other common name(s): nux vomica, poison nut, Quaker buttons, strychnine tree, ma qian zi (also written maqianzi)

Scientific/medical name(s): Strychnos nux-vomica


Strychnos nux-vomica is the name of an evergreen tree native to southeast Asia, especially India and Myanmar, and cultivated elsewhere. Its dried seeds or beans, and sometimes its bark (called nux vomica) are used in herbal remedies. The seeds contain organic substances, strychnine and brucine, that are used in herbal remedies.


Available scientific evidence does not support claims that Strychnos nux-vomica is effective in treating cancer, relieving the side effects of conventional cancer treatment, or in treating any other conditions. The chemicals in the seeds are poisonous and may cause convulsions and death.

How is it promoted for use?

In herbal medicine, Strychnos nux-vomica is recommended for liver cancer, upset stomach, vomiting, abdominal pain, constipation, intestinal irritation, hangovers, heartburn, insomnia, certain heart diseases, circulatory problems, eye diseases, depression, migraine headaches, nervous conditions, problems related to menopause, and respiratory diseases in the elderly. In folk medicine, it is used as a healing tonic and appetite stimulant. Strychnos nux-vomica is used in Chinese herbal medicine to unblock channels and obstructions, reduce swelling, alleviate pain, and to treat abscesses and yin-type ulcers. In traditional Chinese treatment of cancer, it can be used in combination with other herbs.

What does it involve?

The seeds of the Strychnos nux-vomica tree are removed from the ripened berries of the tree and dried in the sun. Sometimes they are heated or further processed, which may reduce the amount of poison in the seeds. Various herbal preparations are made from the dried seeds, including tablets, liquid extracts, and tinctures. Some practitioners use single dosages that range from 20 milligrams to 1 gram. Homeopathic dilutions are also made (see Homeopathy), which contain little, if any, of the actual seeds.

What is the history behind it?

Strychnos nux-vomica is one of the ingredients used, in small amounts, in traditional Chinese herbal treatments for liver cancer and numerous other health problems. Native tribes in Central and South America have also used extracts from this plant for centuries as a medicine to inhibit muscle contractions and as a poison for the tips of arrows. Some physicians used Strychnos nux-vomica in the treatment of stomach cancer in the late nineteenth century. It was given to patients to induce vomiting, which was felt to help relieve the patient's discomfort.

Strychnos nux-vomica is still used as an active ingredient in pest control products, in gopher bait, and in some rat poisons. Today, it is rare to find any form other than the homeopathic preparation recommended for human treatment.

What is the evidence?

Strychnos nux-vomica has not been proven effective for the treatment of any illness. Since the seeds contain strychnine, which is poisonous to humans, conventional medical practitioners do not recommend it as a medicine. Some research has shown that the level of poison in nux vomica preparations may depend greatly on how the seeds are processed.

The herbal remedy is on the Commission E (Germany’s regulatory agency for herbs) list of unapproved herbs, meaning it is not recommended for use because it has not been proven to be safe or effective.

There is no clinical trial evidence of effectiveness as a cancer treatment reported in peer-reviewed English-language journals. Some Chinese studies have reported that Strychnos nux-vomica can kill cancer cells grown in laboratory dishes.

Are there any possible problems or complications?

This product is sold as a dietary supplement in the United States. Unlike companies that produce drugs (which must provide the FDA with results of detailed testing showing their product is safe and effective before the drug is approved for sale), the companies that make supplements do not have to show evidence of safety or health benefits to the FDA before selling their products. Supplement products without any reliable scientific evidence of health benefits may still be sold as long as the companies selling them do not claim the supplements can prevent, treat, or cure any specific disease. Some such products may not contain the amount of the herb or substance that is written on the label, and some may include other substances (contaminants). Though the FDA has written new rules to improve the quality of manufacturing processes for dietary supplements and the accurate listing of supplement ingredients, these rules do not take full effect until 2010. And, the new rules do not address the safety of supplement ingredients or their effects on health when proper manufacturing techniques are used.
Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Strychnine, one of the substances in the seeds of the nux vomica tree, is a poison that, in doses of 5 milligrams or more (as little as one seed), can cause anxiety, restlessness, painful convulsions of the body, breathing difficulties, and even death from suffocation or exhaustion. Long-term intake of even small amounts of strychnine can cause liver damage. This herb should be avoided, especially by women who are pregnant or breast-feeding. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).

Dietary Supplements: What Is Safe?

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer



Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin, TX: American Botanical Council; 1998.

Cai BC, Hattori M, Namba T. Processing of nux vomica. II. Changes in alkaloid composition of the seeds of Strychnos nux-vomica on traditional drug-processing. Chem Pharm Bull (Tokyo). 1990;38:1295-1298.

Cai BC, Wang TS, Kurokawa M, Shiraki K, Hattori M. Cytotoxicities of alkaloids from processed and unprocessed seeds of Strychnos nux-vomica. Zhongguo Yao Li Xue Bao. 1998;19:425-428.

Chan TY. Herbal medicine causing likely strychnine poisoning. Hum Exp Toxicol. 2002;21:467-468.

Chu JHK. Ma qian zi, fan mu bie. Complementary and Alternative Healing University Web site. Accessed at http://alternativehealing.org/ma_qian_zi.htm on August 6, 2008.

Deng X, Yin F, Lu X, Cai B, Yin W. The apoptotic effect of brucine from the seed of Strychnos nux-vomica on human hepatoma cells is mediated via Bcl-2 and Ca2+ involved mitochondrial pathway. Toxicol Sci. 2006;91:59-69.

Gruenwald J. PDR for Herbal Medicines. 3rd ed. Montvale, NJ: Thomson PDR; 2004.

Ma qian zi. Chinese Medicine Tools Web site. Accessed at www.chinesemedicinetools.com/ma-qian-zi on August 6, 2008.

Wang Z, Zhao J, Xing J, He Y, Guo D. Analysis of strychnine and brucine in postmortem specimens by RP-HPLC: a case report of fatal intoxication. J Anal Toxicol. 2004;28:141-144.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 11/28/2008
Last Revised: 11/28/2008