Other common name(s): castor, castor bean, palma christi, Mexico seed, oil plant, mole bean
Scientific/medical name(s): Ricinus communis
Castor oil is extracted from the seeds of Ricinus communis, an herb native to Africa and India. For most uses described here, castor oil is applied to the skin rather than swallowed, but it can be taken by mouth.
Available scientific evidence does not support claims that applying castor oil to the skin (called topical use) is effective in preventing or treating cancer. Taken by mouth, castor oil works as a laxative. And, castor oil is used in mainstream medicine as a way to deliver chemotherapy drugs to cancerous tumors.
How is it promoted for use?
Castor oil, taken by mouth, has been used as a laxative for many years. It may also be used to treat some eye irritations and skin conditions and is used in mainstream medicine to deliver chemotherapy drugs to cancerous tumors.
Naturopathic practitioners (see our document, Naturopathy) and some others claim that castor oil boosts the immune system by increasing white blood cells, which help the body fight infection, and other immune cells. Some also claim that castor oil can help "dissolve" cysts, warts, and tumors, as well as soften bunions and corns. Other claims for castor oil include treating lymphoma, bacterial and viral diseases (including HIV), arthritis, skin and hair conditions, eye irritations, diseases of the colon and gallbladder, bursitis, multiple sclerosis, and Parkinson disease. It is also promoted as a way to "detox" the body and stimulate digestion.
What does it involve?
Treatment involves massaging castor oil into the body or using a warm or hot castor oil pack or compress. The castor oil is massaged along the problem region, spine, abdomen, and sites (or pathways) of lymphatic drainage. If using a compress, the warm castor oil pack is placed over the affected joint or organ and left in place for up to an hour. Promoters say castor oil should be applied until the problem is healed.
Some treatments may include taking small amounts of castor oil by mouth.
What is the history behind it?
Ancient Egyptians were the first to record the use of castor oil for medicinal purposes, and since then it has been used by many cultures as a folk medicine. Castor oil was reportedly used as a medicine during the early Middle Ages in Europe. Edgar Cayce, a medium who entered a trance state to offer patients his thoughts about their diagnosis (and past lives) claimed that castor oil helped to heal the lymphatic tissue in the small intestines, thus increasing absorption of fatty acids and allowing for tissue growth and repair. Most of the plants used in producing castor oil are now grown in India and Brazil.
What is the evidence?
Available scientific evidence does not support claims that castor oil on the skin cures cancer or any other disease. Castor oil is taken by mouth in conventional medicine as a laxative and used as an eye drop to treat some eye irritations. It is also an ingredient in some hair conditioners and skin products. Available scientific evidence does not support other claims.
Oncologists now use castor oil as a vehicle for delivering some chemotherapy drugs to cancerous tumors. A special formula of castor oil called Cremophor EL is used as a carrier for paclitaxel, a drug used to treat metastatic breast cancer and other tumors. Unfortunately, the vehicle sometimes causes problems of its own, including allergic reactions. This has prompted a search for substitute carriers.
Researchers have been studying ricin, a strong poison produced by the castor bean, for a few years now. Most of the studies so far have been done in the lab rather than in humans. But early clinical trials suggest that when combined with an antibody to guide this poison to the malignant cells, ricin may shrink tumors in lymphoma patients.
Ricin is a possible bioterrorism agent, since inhaling, swallowing, or being injected with very small amounts can cause severe illness and death.
Are there any possible problems or complications?
Castor oil is considered safe in proper doses for conventional uses as a laxative. However, side effects can include abdominal pain or cramping, colic, nausea, vomiting, and diarrhea. Long-term use of castor oil can lead to fluid and electrolyte loss.
Women who are pregnant or breast-feeding should not use castor oil, nor should people with intestinal blockage, acute inflammatory intestinal disease, appendicitis, or abdominal pain. Medicines that are dissolved in or based on castor oil compounds can cause allergic reactions.
Castor beans are extremely poisonous and can kill people or animals if chewed or swallowed. Also, handling the seeds can lead to allergic reactions.
Relying on this treatment alone and delaying or avoiding conventional medical care for cancer may have serious health consequences.
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 (1-800-227-2345).
The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management
Belson MG, Schier JG, Patel MM, Case Definitions for Chemical Poisoning. MMWR. 2005; 54(RR01);1-24.
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Fetrow CW, Avila JR. Professional's Handbook of Complementary and Alternative Medicines. Springhouse, Pa: Springhouse Corp; 1999.
Fjällskog ML, Frii L, Bergh J. Paclitaxel-induced cytotoxicity the effects of cremophor EL (castor oil) on two human breast cancer cell lines with acquired multidrug resistant phenotype and induced expression of the permeability glycoprotein. Eur J Cancer. 1994;30A:687-690.
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UPMC Center for Biosecurity. Ricin Fact Sheet. Accessed at http://www.upmc-biosecurity.org/website/focus/agents_diseases/fact_sheets/ricin.html on December 3, 2010.
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 Revised: 03/07/2011