African Coffee Tree, Arandi, Bi Ma Zi, Bofareira, Castorbean, Castor Bean, Castor Bean Plant, Castor Oil, Castor Oil Plant, Castor Seed, Erand, Eranda, Gandharva Hasta, Graine de Ricin, Huile de Ricin, Huile de Ricin Végétale, Mexico Weed, Palma Christi, Ricin, Ricin Commun, Ricin Sanguin, Ricine, Ricino, Ricinus communis, Ricinus sanguines, Tangantangan Oil Plant, Wonder Tree.
Castor is a plant that produces seeds (beans). Castor oil is produced by pressing ripe seeds that have had their outer covering (hull) removed. The hull contains a deadly poison called ricin. Castor oil has been used as medicine for centuries.
Some people apply castor seed paste to the skin as a poultice for inflammatory skin disorders, boils, carbuncles, pockets of infection (abscesses), inflammation of the middle ear, and migraine headaches.
Castor oil is used topically to soften skin, bunions and corns; and to dissolve cysts, growths, and warts. It is also applied to the skin for osteoarthritis. Some women put castor oil inside the vagina for birth control or to cause an abortion. Castor oil is used in the eyes to soothe membranes irritated by dust or other materials.
In manufacturing, castor seeds are used to make paints, varnishes, and lubricating oils.
Ricin from the hull of the castor seed has been tested as a chemical warfare agent. Weapons-grade ricin is purified and produced in particles that are so small they can be breathed in. The smaller the particle size, the more poisonous the ricin. You may remember that ricin was found in letters sent to some Congress members and the White House, and in the possession of people linked to terrorist and antigovernment groups.
How does it work?
Possibly Effective for...
- Bowel preparation before colonoscopy. Some research suggests that taking a single dose of castor oil is effective for bowel preparation in people undergoing a colonoscopy. However, castor oil might not be as effective as other bowel preparations, such as sodium phosphate or bisacodyl plus magnesium citrate.
- Constipation. Castor oil works as a stimulant laxative for reducing constipation when taken by mouth.
- Birth control. There is some evidence that a single dose of castor seeds with the outer coat removed (hulled) can work as a contraceptive for up to 8-12 months.
- Dry eyes. Some research suggests that using eye drops containing castor oil might be effective for people with dry eyes.
- Stimulating full-term labor in pregnant women. A single 60 mL dose of castor oil appears to start labor within 24 hours in at least half of women at term pregnancy who try it. There is also some evidence that women at term pregnancy whose “water has broken” are more likely to go into labor and are less likely to need a Cesarean section if they take castor oil.
Insufficient Evidence to Rate Effectiveness for...
- Skin disorders.
- Swelling (inflammation) of the middle ear.
- Softening cysts.
- Adhesive bowel obstruction.
- Bunions and corns.
- Promoting the flow of breast milk.
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Castor oil is LIKELY SAFE for most people when taken by mouth as a single dose. In some people, castor oil can cause stomach discomfort, cramping, nausea, and faintness.
Castor oil seeds that have had the outer coat removed (hulled) are POSSIBLY SAFE when taken by mouth as a single dose. Also, castor oil eye drops are POSSIBLY SAFE when applied to the eye for up to 30 days.
Castor oil is POSSIBLY UNSAFE when taken by mouth long-term or in large doses. It might cause fluid and potassium loss from the body when used for more than a week or in doses of more than 15-60 mL per day.
The whole seed is UNSAFE to take by mouth. The outer coating (hull) of the castor seed contains a deadly poison. This outer coating can cause nausea; vomiting; diarrhea; abdominal pain; dehydration; shock; blood cell destruction; severe fluid and chemical disturbances; liver, kidney, and pancreas damage; and death. Chewing as few as 1-6 whole seeds can kill an adult. If the seed is swallowed whole, poisoning is less likely; however, prompt medical attention is still an absolute necessity.
Pregnancy and breast-feeding: Using castor oil in pregnant women at term (ready to deliver) is POSSIBLY SAFE. Midwives routinely use castor oil for starting labor in pregnant women who are ready to deliver. However, castor oil should not be used for this purpose without the supervision of a healthcare provider. Also, it is LIKELY UNSAFE to use castor oil in pregnant women who are not at term. It might bring on labor too early. It is UNSAFE for women who are pregnant to take whole castor seeds by mouth, as it can cause serious toxic effects or death.
Don't take castor oil if you are breast-feeding. Not enough research has been done to know whether a mother's use of castor oil is safe for nursing infants.
Intestinal problems: Don't use castor oil if you have a blocked intestine, unexplained stomach pain, or problems with your bile ducts or gall bladder.
Water pills (Diuretic drugs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Castor oil is a laxative. Some laxatives can decrease potassium in the body. "Water pills" can also decrease potassium in the body. Taking castor oil along with "water pills" might decrease potassium in the body too much.
The following doses have been studied in scientific research:
- For constipation: 15 mL of castor oil is commonly used.
- For cleaning the bowel before surgery or examining the colon (colonoscopy): The dose for adults and children over 12 is 15-60 mL of castor oil given 16 hours before the procedure. For children age 2-11 years, 5-15 mL is typically used. In children younger than 2 years, 1-5 mL is commonly used.
- For starting childbirth: A variety of dosage schedules have been used. Single doses vary from 5-120 mL of castor oil. A one-time dose of 60 mL in fruit juice is commonly used. Other dosing schedules that have been used include 5 mL in peppermint tea every 2 hours, 15 mL three times daily, 30 mL every 2 hours, 30 mL every 6 hours, 30 mL every 3 hours for 3 doses, 60 ml daily, and 60 mL daily for 2 days.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Health Solutions From Our Sponsors
Azhari, S., Pirdadeh, S., Lotfalizadeh, M., and Shakeri, M. T. Evaluation of the effect of castor oil on initiating labor in term pregnancy. Saudi.Med J 2006;27(7):1011-1014. View abstract.
Beitz, J. M. Heparin-induced thrombocytopenia syndrome bullous lesions treated with trypsin-balsam of peru-castor oil ointment: a case study. Ostomy.Wound.Manage. 2005;51(6):52-58. View abstract.
Chen, C. C., Ng, W. W., Chang, F. Y., and Lee, S. D. Magnesium citrate-bisacodyl regimen proves better than castor oil for colonoscopic preparation. J.Gastroenterol.Hepatol. 1999;14(12):1219-1222. View abstract.
Di Pascuale, M. A., Goto, E., and Tseng, S. C. Sequential changes of lipid tear film after the instillation of a single drop of a new emulsion eye drop in dry eye patients. Ophthalmology 2004;111(4):783-791. View abstract.
Dodds, W. J., Scanlon, G. T., Shaw, D. K., Stewart, E. T., Youker, J. E., and Metter, G. E. An evaluation of colon cleansing regimens. AJR Am.J Roentgenol. 1977;128(1):57-59. View abstract.
Final report on the safety assessment of Ricinus Communis (Castor) Seed Oil, Hydrogenated Castor Oil, Glyceryl Ricinoleate, Glyceryl Ricinoleate SE, Ricinoleic Acid, Potassium Ricinoleate, Sodium Ricinoleate, Zinc Ricinoleate, Cetyl Ricinoleate, Ethyl Ricinoleate, Glycol Ricinoleate, Isopropyl Ricinoleate, Methyl Ricinoleate, and Octyldodecyl Ricinoleate. Int J Toxicol. 2007;26 Suppl 3:31-77. View abstract.
Fromtling, R. A. Overview of medically important antifungal azole derivatives. Clin.Microbiol.Rev. 1988;1(2):187-217. View abstract.
Goto, E., Shimazaki, J., Monden, Y., Takano, Y., Yagi, Y., Shimmura, S., and Tsubota, K. Low-concentration homogenized castor oil eye drops for noninflamed obstructive meibomian gland dysfunction. Ophthalmology 2002;109(11):2030-2035. View abstract.
Hsieh, J. F., Que, J., Tsai, S. C., Cheng, K. Y., Lin, W. Y., and Wang, S. J. Does bowel preparation improve the quality of abdominal gallium scintigraphy? Nucl.Med Commun. 2000;21(11):1033-1036. View abstract.
Khanal, S., Tomlinson, A., Pearce, E. I., and Simmons, P. A. Effect of an oil-in-water emulsion on the tear physiology of patients with mild to moderate dry eye. Cornea 2007;26(2):175-181. View abstract.
Kolts, B. E., Lyles, W. E., Achem, S. R., Burton, L., Geller, A. J., and MacMath, T. A comparison of the effectiveness and patient tolerance of oral sodium phosphate, castor oil, and standard electrolyte lavage for colonoscopy or sigmoidoscopy preparation. Am.J.Gastroenterol. 1993;88(8):1218-1223. View abstract.
Kris, M. G., Gralla, R. J., Clark, R. A., Tyson, L. B., and Groshen, S. Control of chemotherapy-induced diarrhea with the synthetic enkephalin BW942C: a randomized trial with placebo in patients receiving cisplatin. J Clin.Oncol. 1988;6(4):663-668. View abstract.
Luderer, J. R., Demers, L. M., Nomides, C. T., and Hayes, A. H., Jr. Mechanism of action of castor oil: a biochemical link to the prostaglandins. Adv.Prostaglandin Thromboxane Res. 1980;8:1633-1635. View abstract.
Maier, M., Staupendahl, D., Duerr, H. R., and Refior, H. J. Castor oil decreases pain during extracorporeal shock wave application. Arch.Orthop.Trauma Surg. 1999;119(7-8):423-427. View abstract.
Marmion, L. C., Desser, K. B., Lilly, R. B., and Stevens, D. A. Reversible thrombocytosis and anemia due to miconazole therapy. Antimicrob.Agents Chemother. 1976;10(3):447-449. View abstract.
Micha, J. P., Goldstein, B. H., Birk, C. L., Rettenmaier, M. A., and Brown, J. V., III. Abraxane in the treatment of ovarian cancer: the absence of hypersensitivity reactions. Gynecol.Oncol. 2006;100(2):437-438. View abstract.
Mitri, F., Hofmeyr, G. J., and van Gelderen, C. J. Meconium during labour--self-medication and other associations. S.Afr.Med J 4-4-1987;71(7):431-433. View abstract.
Novetsky, G. J., Turner, D. A., Ali, A., Raynor, W. J., Jr., and Fordham, E. W. Cleansing the colon in gallium-67 scintigraphy: a prospective comparison of regimens. AJR Am J Roentgenol. 1981;137(5):979-981. View abstract.
Okwuasaba, F. K., Osunkwo, U. A., Ekwenchi, M. M., Ekpenyong, K. I., Onwukeme, K. E., Olayinka, A. O., Uguru, M. O., and Das, S. C. Anticonceptive and estrogenic effects of a seed extract of Ricinus communis var. minor. J Ethnopharmacol. 1991;34(2-3):141-145. View abstract.
Pearce, E. I., Tomlinson, A., Blades, K. J., Falkenberg, H. K., Lindsay, B., and Wilson, C. G. Effect of an oil and water emulsion on tear evaporation rate. Adv.Exp.Med Biol. 2002;506(Pt A):419-423. View abstract.
Present, A. J., Jansson, B., Burhenne, H. J., Dodd, G. D., Goldberg, H. I., Goldstein, H. M., Miller, R. E., Nelson, J. A., and Stewart, E. T. Evaluation of 12 colon-cleansing regimens with single-contrast barium enema. AJR Am.J Roentgenol. 1982;139(5):855-860. View abstract.
Rischin, D., Webster, L. K., Millward, M. J., Linahan, B. M., Toner, G. C., Woollett, A. M., Morton, C. G., and Bishop, J. F. Cremophor pharmacokinetics in patients receiving 3-, 6-, and 24-hour infusions of paclitaxel. J Natl.Cancer Inst. 9-18-1996;88(18):1297-1301. View abstract.
Roberge-Wade, A. P., Hosking, D. H., MacEwan, D. W., and Ramsey, E. W. The excretory urogram bowel preparation--is it necessary? J Urol. 1988;140(6):1473-1474. View abstract.
Ryan, J., Leighton, J., Kirksey, D., and McMahon, G. Evaluation of an enkephalin analog in men with castor oil-induced diarrhea. Clin.Pharmacol.Ther. 1986;39(1):40-42. View abstract.
Sall, K., Stevenson, O. D., Mundorf, T. K., and Reis, B. L. Two multicenter, randomized studies of the efficacy and safety of cyclosporine ophthalmic emulsion in moderate to severe dry eye disease. CsA Phase 3 Study Group. Ophthalmology 2000;107(4):631-639. View abstract.
Scarpa, A. and Guerci, A. Various uses of the castor oil plant (Ricinus communis L.). A review. J.Ethnopharmacol. 1982;5(2):117-137. View abstract.
Stevenson, D., Tauber, J., and Reis, B. L. Efficacy and safety of cyclosporin A ophthalmic emulsion in the treatment of moderate-to-severe dry eye disease: a dose-ranging, randomized trial. The Cyclosporin A Phase 2 Study Group. Ophthalmology 2000;107(5):967-974. View abstract.
Strates, B. S. and Hofmann, L. M. A randomized study of two preparations for large bowel radiology. Pharmatherapeutica 1987;5(1):57-61. View abstract.
Sugar, A. M., Salibian, M., and Goldani, L. Z. Saperconazole therapy of murine disseminated candidiasis: efficacy and interactions with amphotericin B. Antimicrob.Agents Chemother. 1994;38(2):371-373. View abstract.
Tayrouz, Y., Ding, R., Burhenne, J., Riedel, K. D., Weiss, J., Hoppe-Tichy, T., Haefeli, W. E., and Mikus, G. Pharmacokinetic and pharmaceutic interaction between digoxin and Cremophor RH40. Clin.Pharmacol.Ther. 2003;73(5):397-405. View abstract.
Vieira, C., Evangelista, S., Cirillo, R., Lippi, A., Maggi, C. A., and Manzini, S. Effect of ricinoleic acid in acute and subchronic experimental models of inflammation. Mediators.Inflamm. 2000;9(5):223-228. View abstract.
Vitetta, E. S., Smallshaw, J. E., Coleman, E., Jafri, H., Foster, C., Munford, R., and Schindler, J. A pilot clinical trial of a recombinant ricin vaccine in normal humans. Proc.Natl.Acad.Sci U.S.A 2-14-2006;103(7):2268-2273. View abstract.
Yang, H. C., Sheu, M. H., Wang, J. H., and Chang, C. Y. Bowel preparation of outpatients for intravenous urography: efficacy of castor oil versus bisacodyl. Kaohsiung.J Med Sci 2005;21(4):153-158. View abstract.
Zhang, K. E., Wu, E., Patick, A. K., Kerr, B., Zorbas, M., Lankford, A., Kobayashi, T., Maeda, Y., Shetty, B., and Webber, S. Circulating metabolites of the human immunodeficiency virus protease inhibitor nelfinavir in humans: structural identification, levels in plasma, and antiviral activities. Antimicrob.Agents Chemother. 2001;45(4):1086-1093. View abstract.
Allaire AD, Moos MK, Wells SR. Complementary and alternative medicine in pregnancy: A survey of North Carolina certified nurse-midwives. Obstet Gynecol 2000;95:19-23. View abstract.
Audi J, Belson M, Patel M, et al. Ricin poisoning: a comprehensive review. JAMA 2005;294:2342-51. View abstract.
Challoner KR, McCarron MM. Castor bean intoxication. Ann Emerg Med 1990;19:1177-83. View abstract.
Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
Das SC, Isichei CO, Okwuasaba FK, et al. Chemical, pathological and toxicological studies of the effects of RICOM-1013-J of Ricinus communis var minor on women volunteers and rodents. Phytother Res 2000;14:15-9. View abstract.
Garry D, Figueroa R, Guillaume J, Cucco V. Use of castor oil in pregnancies at term. Altern Ther Health Med 2000;6:77-9. View abstract.
Isichei CO, Das SC, Ogunkeye OO, et al. Preliminary clinical investigation of the contraceptive efficacy and chemical pathological effects of RICOM-1013-J of Ricinus communis var minor on women volunteers. Phytother Res 2000;14:40-2. View abstract.
McFarlin BL, Gibson MH, O'Rear J, Harman P. A national survey of herbal preparation use by nurse-midwives for labor stimulation. Review of the literature and recommendations for practice. J Nurse Midwifery 1999;44:205-16. View abstract.
Melia AT, Koss-Twardy SG, Zhi J. The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers. J Clin Pharmacol 1996;36:647-53. View abstract.
Palatnick W, Tenenbein M. Hepatotoxicity from castor bean ingestion in a child. J Toxicol Clin Toxicol 2000;38:67-9. View abstract.
Steingrub JS, Lopez T, Teres D, et al. Amniotic fluid embolism associated with castor oil ingestion. Crit Care Med 1988;16:642-3. View abstract.
Vehmeyer K, Hajito T, Hostanska K, et al. Lectin-induced increase in clonogenic growth of haematopoietic progenitor cells. Eur J Haematol 1998;60:16-20. View abstract.