Editing Castor oil

{{Short description|Vegetable oil pressed from castor beans}}
{{distinguish|Castoreum}}
{{for|the fictional character|Castor Oyl}}
{{multiple image
| border                   = 
| total_width              = 300
| image_style              = border:none;
| perrow                   = 1/2
| image3 = Plants (4163856656).jpg
| image2 = Castor oil seeds in the Royal Botanic Gardens, Kew Economic Botany Collection.jpg
| image1 = Castor oil.jpg
}}

'''Castor oil''' is a [[vegetable oil]] pressed from [[castor bean]]s, the seeds of the plant ''Ricinus communis''.<ref name="ullmanns">{{cite book |first= Alfred |last= Thomas |chapter= Fats and Fatty Oils |title= Ullmann's Encyclopedia of Industrial Chemistry |year= 2005 |publisher= Wiley-VCH |location= Weinheim |doi= 10.1002/14356007.a10_173|isbn= 978-3527306732 }}</ref> The seeds are 40 to 60 percent oil.<ref>{{Cite book |last=Aggrawal |first=Dr Anil |url=https://books.google.com/books?id=Tl0qDAAAQBAJ&pg=PA532 |title=APC Forensic Medicine and Toxicology for MBBS |publisher=Avichal Publishing Company |isbn=978-81-7739-491-7 |pages=530 |language=en |archive-date=2024-08-17 |access-date=2024-08-17 |archive-url=https://web.archive.org/web/20240817075734/https://books.google.com/books?id=Tl0qDAAAQBAJ&pg=PA532 |url-status=live }}</ref> It is a colourless or pale yellow liquid with a distinct taste and odor. Its [[boiling point]] is {{convert|313|C|F}} and its [[density]] is 0.961&nbsp;g/cm<sup>3</sup>.<ref>{{cite book |title= Aldrich Handbook of Fine Chemicals and Laboratory Equipment |publisher= Sigma-Aldrich |year= 2003}}{{Full citation needed |date= December 2014}}</ref> It includes a mixture of [[triglyceride]]s in which about 90 percent of fatty acids are [[Ricinoleic acid|ricinoleates]]. [[Oleic acid]] and [[linoleic acid]] are the other significant components.

Some 270,000–360,000 tonnes (600–800 million pounds) of castor oil are produced annually for a variety of uses.<ref name="onlinelibrary.wiley.com"/> Castor oil and its derivatives are used in the manufacturing of [[soap]]s, [[lubricant]]s, hydraulic and [[brake fluid]]s, [[paint]]s, [[dye]]s, [[coating]]s, [[ink]]s, cold-resistant [[plastic]]s, [[wax]]es and polishes, [[nylon]], and [[perfume]]s.<ref name="onlinelibrary.wiley.com">{{cite journal |title= Castor oil as a renewable resource for the chemical industry |last1= Mutlu |first1= H |last2= Meier |first2= MAR |date= January 2010 |journal= European Journal of Lipid Science and Technology |volume= 112 |issue= 1 |pages= 10–30 |doi= 10.1002/ejlt.200900138}}</ref>

==Etymology==
The name probably comes from a confusion between the ''[[Ricinus]]'' plant that produces it and another plant, the ''[[Vitex agnus-castus]]''.<ref>{{cite news
 | url=https://www2.palomar.edu/users/warmstrong/plmar99.htm
 | title=The Castor Bean: A Plant Named After A Tick
 | publisher=Wayne's Word: An Online Textbook of Natural History
 | date=March 1999
 | access-date=2020-04-26
 | archive-date=2021-11-15
 | archive-url=https://web.archive.org/web/20211115044547/https://www2.palomar.edu/users/warmstrong/plmar99.htm
 | url-status=dead
 }}</ref><ref>{{Cite book |last=Jacob |first=Irene |title=The Healing Past |chapter-url=https://brill.com/view/book/edcoll/9789004377325/BP000006.xml |chapter=Ricinus Communis—The Miracle Tree through Four Thousand Years |date=1993-01-01 |publisher=BRILL |isbn=978-90-04-37732-5 |editor-last=Jacob |pages=81–93 |doi=10.1163/9789004377325_006 |editor-last2=Jacob |archive-date=2022-06-21 |access-date=2024-11-22 |archive-url=https://web.archive.org/web/20220621202144/https://brill.com/view/book/edcoll/9789004377325/BP000006.xml |url-status=live }}</ref> An alternative etymology, though, suggests that it was used as a replacement for [[castoreum]].<ref>{{cite web |url-status= usurped |url= http://www.billcasselman.com/cwod_archive/beaver_castor_two.htm |archive-url= https://web.archive.org/web/20110203042939/http://www.billcasselman.com/cwod_archive/beaver_castor_two.htm |archive-date= 2011-02-03 |title= Castor |work= Bill Casselman's Canadian Word of the Day |last= Casselman |first= William Gordon |access-date= 2014-08-09 }}</ref>

==History==
Use of castor oil as a laxative is attested to in the {{circa|1550 BCE}} [[Ebers Papyrus]],<ref>{{cite book |last=Bryan |first=Cyril P. |date=1930 |title=The Papyrus Ebers, Translated from the German Version by Cyril P. Bryan |url=http://oilib.uchicago.edu/books/bryan_the_papyrus_ebers_1930.pdf |archive-url=https://web.archive.org/web/20130921055114/http://oilib.uchicago.edu/books/bryan_the_papyrus_ebers_1930.pdf |archive-date=2013-09-21 |location=London |publisher=Geoffrey Bles |page=44 }}</ref> and it was in use several centuries earlier.<ref>Bryan, p. xvii</ref> Midwifery manuals from the 19th century recommended castor oil and 10 drops of [[laudanum]] for relieving "false pains."<ref>{{Cite web |last=Barnes |first=Robert Sydenham Fancourt |title=A Manual of Midwifery for Midwives |edition=2nd |location=London |year=1883 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hc4qpg&seq=102 |access-date=2024-08-17 |via=HathiTrust |language=en-gb |archive-date=2024-08-17 |archive-url=https://web.archive.org/web/20240817071057/https://babel.hathitrust.org/cgi/pt?id=hvd.hc4qpg&seq=102 |url-status=live }}</ref>

==Composition==
[[Image:Castor oil (Main Component Structural Formulae) V2.svg|thumb|Structure of the major component of castor oil: triester of glycerol and ricinoleic acid]]
Castor oil is well known as a source of [[ricinoleic acid]], a [[unsaturated fat|monounsaturated]], 18-carbon [[fatty acid]]. Among fatty acids, ricinoleic acid is unusual in that it has a [[hydroxyl]] [[functional group]] on the 12th carbon atom. This functional group causes ricinoleic acid (and castor oil) to be more [[chemical polarity|polar]] than most fats. The chemical reactivity of the alcohol group also allows chemical [[derivatization]] that is not possible with most other seed oils.

Because of its ricinoleic acid content, castor oil is a valuable chemical in feedstocks, commanding a higher price than other seed oils. As an example, in July 2007, Indian castor oil sold for about [[United States dollar|US$]]0.90/kg ($0.41/lb),{{citation needed|date=August 2019}} whereas U.S. [[soybean]], [[sunflower oil|sunflower]], and [[canola]] oils sold for about $0.30/kg ($0.14/lb).<ref>{{cite web|url=http://www.fas.usda.gov/oilseeds/circular/2007/July/oilseedsfull0707.pdf |date=July 2007 |title=Seed Oil Prices |publisher=[[United States Department of Agriculture]] |page=31 |access-date=2008-08-10 |url-status=dead |archive-url=https://web.archive.org/web/20080406064840/http://www.fas.usda.gov/oilseeds/circular/2007/July/oilseedsfull0707.pdf |archive-date=April 6, 2008 }}</ref>

{| class="wikitable"
|+Average composition of castor seed oil / fatty acids
|-
! scope="col" | Acid name
! scope="col" | Range
! scope="col" | Type
|-
| [[Ricinoleic acid]]
| align=center | 85–95
| ω−9
|-
| [[Oleic acid]]
| align=center | 2–6
| ω−9
|-
| [[Linoleic acid]]
| align=center | 1–5
| ω−6
|-
| [[alpha-Linolenic acid|α-Linolenic acid]]
| align=center | 0.5–1
| ω−3
|-
| [[Stearic acid]]
| align=center | 0.5–1
| saturated
|-
| [[Palmitic acid]]
| align=center | 0.5–1
| saturated
|-
| Dihydroxy[[stearic acid]]
| align=center | 0.3–0.5
| saturated
|-
| Others
| align=center | 0.2–0.5
| 
|}
<!-- Todo; oil fat comparison chart ... -->

==Human uses==
Castor oil has been used orally to relieve [[constipation]] or to evacuate the [[bowel]] before [[intestine|intestinal]] surgery.<ref name="drugs">{{cite web |title=Castor oil |url=https://www.drugs.com/monograph/castor-oil.html |publisher=Drugs.com |access-date=20 April 2023 |date=3 October 2022 |archive-date=20 April 2023 |archive-url=https://web.archive.org/web/20230420203550/https://www.drugs.com/monograph/castor-oil.html |url-status=live }}</ref> The [[laxative]] effect of castor oil is attributed to [[ricinoleic acid]], which is produced by [[hydrolysis]] in the [[small intestine]].<ref name=drugs/> Use of castor oil for simple constipation is medically discouraged because it may cause violent [[diarrhea]].<ref name=drugs/>

===Food and preservative===
In the food industry, food-grade castor oil is used in food additives, flavorings, candy (e.g., [[polyglycerol polyricinoleate]] in [[chocolate]]),<ref>{{Cite journal |last1= Wilson |first1= R |last2= Van Schie |first2= BJ |last3= Howes |first3= D |title= Overview of the preparation, use and biological studies on polyglycerol polyricinoleate (PGPR) |journal= [[Food and Chemical Toxicology]] |volume= 36 |issue= 9–10 |pages= 711–8 |year= 1998 |pmid= 9737417 |doi= 10.1016/S0278-6915(98)00057-X}}</ref> as a mold inhibitor, and in packaging. Polyoxyethylated castor oil (e.g., [[Kolliphor EL]])<ref>{{cite web|url=http://www.sfm.state.or.us/cr2k_subdb/msds/cremophor_el_castor_oil.pdf|title=Safety datawsheet cremophor El Castor Oil|website=www.sfm.state.or.us|access-date=2016-12-05|archive-date=2017-12-06|archive-url=https://web.archive.org/web/20171206224827/http://www.sfm.state.or.us/cr2k_subdb/msds/cremophor_el_castor_oil.pdf|url-status=dead}}</ref> is also used in the food industries.<ref>{{Cite journal |doi= 10.1590/S0001-37652004000100005 |last1= Busso |first1= C |last2= Castro-Prado |first2= MA |title= Cremophor EL stimulates mitotic recombination in uvsH/uvsH diploid strain of Aspergillus nidulans |journal= Anais da Academia Brasileira de Ciências |volume=76 |issue=1 |pages=49–55 |date=March 2004 |pmid=15048194 |doi-access= free }}</ref> In [[India]], [[Pakistan]], and [[Nepal]], food grains are [[Preservative|preserved]] by the application of castor oil. It stops [[rice]], [[wheat]], and [[Legume#Terminology|pulses]] from rotting. For example, the legume [[pigeon pea]] is commonly available coated in oil for extended storage.

=== Emollient ===
[[File:Scott & Bowne's Palatable Castor Oil.jpg|thumb|Advertisement of castor oil as a medicine by Scott & Bowne Company, 19th century]]
Castor oil has been used in [[Cosmetics|cosmetic]] products included in creams and as a [[moisturizer]]. It is often combined with [[zinc oxide]] to form an [[emollient]] and [[astringent]], zinc and castor oil cream, which is commonly used to treat infants for [[nappy rash]].<ref>{{cite book |last1=Williams |first1=Cheryll |title=Medicinal Plants in Australia Volume 3: Plants, Potions and Poisons |date=1 July 2012 |publisher=Rosenberg Publishing |isbn=978-1-925078-07-7 |page=309 |url=https://books.google.com/books?id=ieVUAQAAQBAJ&pg=PA309 |access-date=8 March 2023 |language=en |archive-date=20 April 2023 |archive-url=https://web.archive.org/web/20230420114645/https://books.google.com/books?id=ieVUAQAAQBAJpg=PA309 |url-status=live }}</ref><ref>{{cite book |last1=Nathan |first1=Alan |title=Non-prescription Medicines |date=2010 |publisher=Pharmaceutical Press |isbn=978-0-85369-886-9 |page=206 |url=https://books.google.com/books?id=lW-0IoSYMBYC&dq=zinc+and+castor+oil+cream&pg=PA206 |access-date=8 March 2023 |language=en |archive-date=20 April 2023 |archive-url=https://web.archive.org/web/20230420114755/https://books.google.com/books?id=lW-0IoSYMBYC&dq=zinc+and+castor+oil+cream&pg=PA206 |url-status=live }}</ref>

=== Medicine ===
Castor oil is used as a vehicle for serums administering steroid hormones such as [[estradiol valerate]] via [[Intramuscular injection|intramuscular]] or [[Subcutaneous administration|subcutaneous]] injection.<ref>{{Cite journal |last1=Huber |first1=C. Riffkin R. |last2=Keysser |first2=C. H. |date=1964-08-01 |title=Castor Oil as a Vehicle for Parenteral Administration of Steroid Hormones |url=https://www.sciencedirect.com/science/article/abs/pii/S0022354915344890 |journal=Journal of Pharmaceutical Sciences |volume=53 |issue=8 |pages=891–895 |doi=10.1002/jps.2600530809 |pmid=14241800 |issn=0022-3549}}</ref><ref>{{Cite web |title=ESTRADIOL VALERATE INJECTION, USP Rx Only |url=https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=2984bce2-89bf-4768-a1ca-ccf03b1197be&type=display |access-date=2024-12-16 |website=dailymed.nlm.nih.gov}}</ref>

=== Alternative medicine ===
Despite the lack of evidence, castor oil is sometimes claimed to be able to cure diseases. According to the [[American Cancer Society]], "available scientific evidence does not support claims that castor oil on the skin cures cancer or any other disease."<ref>{{cite web |date=March 2011 |title=Castor Oil |url=http://www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/manualhealingandphysicaltouch/castor-oil |archive-url=https://web.archive.org/web/20130209065404/http://www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/manualhealingandphysicaltouch/castor-oil |archive-date=2013-02-09 |access-date=2013-09-22 |publisher=[[American Cancer Society]]}}</ref>

=== Childbirth ===
[[File:Huile de ricin naturafro.jpg|thumb|Castor oil]]
Despite some undesirable side effects, castor oil is used for labor induction. There is no high-quality research proving that ingestion of castor oil results in [[cervical ripening]] or [[Labor induction|induction of labor]]; there is, however, evidence that taking it causes [[nausea]] and diarrhea.<ref name=":1" /><ref name=":2" /> A [[systematic review]] of "three trials, involving 233 women, found there has not been enough research done to show the effects of castor oil on ripening the [[cervix]] or inducing labour or compare it to other methods of induction. The review found that all women who took castor oil by mouth felt nauseous. More research is needed into the effects of castor oil to induce labour."<ref name=":1">{{Cite journal |doi = 10.1002/14651858.CD003099.pub2 |title= Castor oil, bath and/or enema for cervical priming and induction of labour |journal= [[Cochrane Library|Cochrane Database of Systematic Reviews]] |year= 2013 |issue= 7 |page= CD003099 |last1= Kelly |first1= AJ |last2= Kavanagh |first2= J |last3= Thomas |first3= J |volume= 2013 |pmid=23881775|pmc= 7138266 }}</ref><ref name=":2">{{cite journal |vauthors=Carlson NS, Dunn Amore A, Ellis JA, Page K, Schafer R |title=American College of Nurse-Midwives Clinical Bulletin Number 18: Induction of Labor |journal=J Midwifery Women's Health |volume=67 |issue=1 |pages=140–149 |date=January 2022 |pmid=35119782 |pmc=9026716 |doi=10.1111/jmwh.13337 |type=Review |quote=Despite its long history of use for inducing onset of spontaneous labor, castor oil has minimal evidence to support its efficacy and is commonly associated with adverse effects of nausea, vomiting, and diarrhea.}}</ref> Castor oil is still used for labor induction in environments where modern drugs are not available; a review of pharmacologic, mechanical, and "[[Alternative medicine|complementary]]" methods of labor induction published in 2024 by the ''[[American Journal of Obstetrics and Gynecology]]'' stated that castor oil's physiological effect is poorly understood but "given gastrointestinal [[symptomatology]], a [[prostaglandin]] mediation has been suggested but not confirmed."<ref>{{cite journal |vauthors=Sanchez-Ramos L, Levine LD, Sciscione AC, Mozurkewich EL, Ramsey PS, Adair CD, Kaunitz AM, McKinney JA |title=Methods for the induction of labor: efficacy and safety |journal=Am J Obstet Gynecol |volume=230 |issue=3S |pages=S669–S695 |date=March 2024 |pmid=38462252 |doi=10.1016/j.ajog.2023.02.009 |type=Review|doi-access=free }}</ref> According to ''Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk'' (2008), castor oil should not be ingested or used topically by pre-term pregnant women.<ref name=":3">{{Cite book |last1=Briggs |first1=Gerald G. |chapter-url=https://books.google.com/books?id=YOEV2w3XTxsC&dq=%22castor+oil%22+abortifacient&pg=PA271 |title=Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk |last2=Freeman |first2=Roger K. |last3=Yaffe |first3=Sumner J. |date=2008 |publisher=Lippincott Williams & Wilkins |isbn=978-0-7817-7876-3 |pages=271–273 |language=en |chapter=Castor Oil (Laxative/Oxytocic)}}</ref> There is no data on the potential toxicity of castor oil for nursing mothers.<ref name=":3" />

=== Punishment ===
[[File:Kellogg's Perfected Tasteless Castor Oil, Spencer Kellogg and Sons Inc., New York 03.jpg|thumb|Warning label on a bottle of Kellogg's Perfected Tasteless Castor Oil, [[Spencer Kellogg & Sons, Inc.]], New York]]
Since children commonly strongly dislike the taste of castor oil, some parents [[child discipline|punished children]] with a dose of it.<ref>For an American example see {{cite book|author=David J. Rothman|title=Conscience and Convenience: The Asylum and Its Alternatives in Progressive America|url=https://books.google.com/books?id=BfCrAAAAQBAJ&pg=PA279|year=1980|publisher=Transaction Publishers|page=279|access-date=2015-10-29|isbn=9780202365091|archive-date=2023-01-14|archive-url=https://web.archive.org/web/20230114165300/https://books.google.com/books?id=BfCrAAAAQBAJ&pg=PA279|url-status=live}}</ref><ref>For a Canadian examples see {{cite book|author=Neil Sutherland|title=Growing Up: Childhood in English Canada from the Great War to the Age of Television|url=https://archive.org/details/growingupchildho0000suth|url-access=registration|year=1997|publisher=University of Toronto Press|page=[https://archive.org/details/growingupchildho0000suth/page/87 87]|access-date=2015-10-29|isbn=9780802079831}}</ref> Physicians recommended against the practice because it may associate medicines with punishment and make children afraid of the doctor.<ref>{{cite book|title=Journal of the American Medical Association|url=https://books.google.com/books?id=Mp0hAQAAMAAJ&pg=PA1699|year=1919|publisher=American Medical Association.|page=1699|access-date=2015-10-29|archive-date=2023-01-14|archive-url=https://web.archive.org/web/20230114165301/https://books.google.com/books?id=Mp0hAQAAMAAJ&pg=PA1699|url-status=live}}</ref>

=== Use in torture ===
A heavy dose of castor oil could be used as a humiliating punishment for adults. Colonial officials used it in the [[British Raj]] (India) to deal with recalcitrant servants.<ref>{{cite book|author=Cecilia Leong-Salobir|title=Food Culture in Colonial Asia: A Taste of Empire|url=https://books.google.com/books?id=Q0a4QLN1CQgC&pg=PA66|year=2011|publisher=Taylor & Francis|page=66|isbn=9781136726545|access-date=2016-01-08|archive-date=2023-01-14|archive-url=https://web.archive.org/web/20230114165305/https://books.google.com/books?id=Q0a4QLN1CQgC&pg=PA66|url-status=live}}</ref> 
Belgian military officials prescribed heavy doses of castor oil in [[Belgian Congo]] as a punishment for being too sick to work.<ref>{{Cite book|title=King Leopold's ghost: a story of greed, terror, and heroism in Colonial Africa|last=Adam.|first=Hochschild|date=1999|publisher=Houghton Mifflin|isbn=978-0547525730|edition=1st Mariner books|location=Boston|pages=166|oclc=759834634}}</ref> Castor oil was also a tool of punishment favored by the [[Falangism|Falangist]] and later [[Francoist Spain]] during and following the [[Spanish Civil War]].<ref name=":0">{{Cite book |last=Preston |first=Paul |url=http://archive.org/details/spanishholocaust0000pres |title=The Spanish holocaust : inquisition and extermination in twentieth-century Spain |date=2012 |publisher=New York : W.W. Norton & Co. |others=Internet Archive |isbn=978-0-393-06476-6 |pages=139, 156, 169, 187, 201, 202, 212, 310, 315, 321, 326, 449}}</ref> Its use as a form of [[Gender violence and rape in Francoist Spain and the democratic transition|gendered violence]] to repress women was especially prominent.<ref name=":0" /><ref name="Juan">{{Cite web |last=Juan |first=Carmen Miguel |date=2016-04-06 |title=Mujeres y dictadura franquista: la historia silenciada |url=https://www.eldiario.es/contrapoder/mujeres-dictadura-franquista_132_4067401.html |access-date=2023-12-16 |website=elDiario.es |language=es |archive-date=2023-12-16 |archive-url=https://web.archive.org/web/20231216201135/https://www.eldiario.es/contrapoder/mujeres-dictadura-franquista_132_4067401.html |url-status=live }}</ref> 
This began during the war where [[Nationalist faction (Spanish Civil War)|Nationalist]] forces would specifically target  Republican-aligned women, both troops and civilians, who lived in [[Republican faction (Spanish Civil War)|Republican]]-controlled areas.<ref name=":0" /> 
The forced drinking of castor oil occurred alongside sexual assault, rape, torture and murder of these women.<ref name=":0" /><ref name="Juan"/> Its most notorious use as punishment came in [[History of Italy as a monarchy and in the World Wars|Fascist Italy]] under [[Benito Mussolini]]. It was a favorite tool used by the [[Blackshirts]] to intimidate and humiliate their opponents.<ref>{{cite encyclopedia|title=Italy The rise of Mussolini |encyclopedia=Encyclopædia Britannica Online |publisher=Encyclopædia Britannica |year=2007 |url=http://britannica.com/eb/article-27762/Italy |access-date=2007-08-03 |url-status=dead |archive-url=https://web.archive.org/web/20071014023531/http://britannica.com/eb/article-27762/Italy |archive-date=October 14, 2007 }}</ref><ref>{{Cite news   | title =Benito's Birthday   | publisher =Time, in partnership with CNN   | date = August 6, 1923   | url =http://www.time.com/time/magazine/article/0,9171,716284,00.html?iid=chix-sphere   | archive-url =https://web.archive.org/web/20080407195821/http://www.time.com/time/magazine/article/0,9171,716284,00.html?iid=chix-sphere   | url-status =dead   | archive-date =April 7, 2008   | access-date =2007-08-03  }}</ref><ref>{{Cite book   | last =Bosworth   | first =R. J. B.   | title =Mussolini   | publisher =Arnold/Oxford Univ. Press   | year= 2002   | location =New York   | isbn =978-0-340-73144-4 }}</ref> 
[[Political dissident]]s were force-fed large quantities of castor oil by [[Fascism|fascist]] squads so as to induce bouts of extreme diarrhea in the victims. This technique was said to have been originated by [[Gabriele D'Annunzio]] or [[Italo Balbo]].<ref>"Bearded like a medieval condottiere, bluff yet suave, fearless and supple, [Italo Balbo] was not the type to pass unnoticed anywhere. His admirers here chose to forget the Blackshirt club-wielder and reputed inventor of the castor-oil treatment for Fascist foes"<br/> [https://www.nytimes.com/1940/07/01/archives/marshal-balbo.html Marshal Balbo] {{Webarchive|url=https://web.archive.org/web/20210429102059/https://www.nytimes.com/1940/07/01/archives/marshal-balbo.html |date=2021-04-29 }}, ''[[The New York Times]]'', July 1, 1940, p. 18.</ref> This form of torture was potentially deadly, as the administration of the castor oil was often combined with [[Baton (law enforcement)|nightstick]] beatings, especially to the [[Buttocks|rear]], so that the resulting diarrhea would not only lead to dangerous dehydration but also [[Infection|infect]] the open wounds from the beatings. However, even those victims who survived had to bear the [[humiliation]] of the laxative effects resulting from excessive consumption of the oil.<ref name="Did Mussolini">{{cite web |author=Cecil Adams |url=https://www.straightdope.com/21342121/did-mussolini-use-castor-oil-as-an-instrument-of-torture |title=Did Mussolini use castor oil as an instrument of torture? |publisher=The Straight Dope |date=1994-04-22 |access-date=2014-08-09 |archive-date=2020-11-01 |archive-url=https://web.archive.org/web/20201101021504/https://www.straightdope.com/21342121/did-mussolini-use-castor-oil-as-an-instrument-of-torture |url-status=live }}</ref>

==Industrial uses==

===Coatings===
Castor oil is used as a biobased [[polyol]] in the [[polyurethane]] industry. The average functionality (number of [[hydroxyl]] groups per triglyceride molecule) of castor oil is 2.7, so it is widely used as a rigid polyol and in coatings.<ref name=ullmanns/> 
One particular use is in a polyurethane concrete where a castor-oil emulsion is reacted with an isocyanate (usually polymeric [[methylene diphenyl diisocyanate]]) and a [[cement]] and [[construction aggregate]]. This is applied fairly thickly as a slurry, which is self-levelling. This base is usually further coated with other systems to build a resilient floor.<ref>{{Cite journal|last=Howarth|first=GA|date=June 2003|title=Polyurethanes, polyurethane dispersions and polyureas: Past, present and future|journal=Surface Coatings International Part B: Coatings Transactions|language=en|volume=86|issue=2|pages=111–118|doi=10.1007/bf02699621|s2cid=93574741|issn=1476-4865}}</ref> Castor oil is not a [[drying oil]], meaning that it has a low reactivity with air compared with oils such as [[linseed oil]] and [[tung oil]]. However, dehydration of castor oil yields linoleic acids, which do have drying properties.<ref name=ullmanns/> 
In this process, the OH group on the ricinoleic acid along with a hydrogen from the next carbon atom are removed, forming a double bond which then has oxidative cross-linking properties and yields the drying oil. It is considered a vital raw material.<ref>{{Cite journal |last=Ogunniyi |first=D. S. |date=2006-06-01 |title=Castor oil: A vital industrial raw material |url=https://www.sciencedirect.com/science/article/pii/S0960852405002026 |journal=Bioresource Technology |language=en |volume=97 |issue=9 |pages=1086–1091 |doi=10.1016/j.biortech.2005.03.028 |pmid=15919203 |bibcode=2006BiTec..97.1086O |issn=0960-8524 |access-date=2023-03-09 |archive-date=2016-11-30 |archive-url=https://web.archive.org/web/20161130045802/http://www.sciencedirect.com/science/article/pii/S0960852405002026 |url-status=live }}</ref>

===Chemical precursor===
Castor oil can react with other materials to produce other chemical compounds that have numerous applications.<ref>{{Cite journal |last1=Ma |first1=Yufeng |last2=Wang |first2=Rui |last3=Li |first3=Qiaoguang |last4=Li |first4=Mei |last5=Liu |first5=Chengguo |last6=Jia |first6=Puyou |date=2021-03-24 |title=Castor oil as a platform for preparing bio-based chemicals and polymer materials |url=https://www.icevirtuallibrary.com/doi/10.1680/jgrma.20.00085 |journal=Green Materials |volume=10 |issue=3 |pages=99–109 |doi=10.1680/jgrma.20.00085 |s2cid=233687152 |issn=2049-1220 |access-date=2022-04-18 |archive-date=2023-01-31 |archive-url=https://web.archive.org/web/20230131222012/https://www.icevirtuallibrary.com/doi/10.1680/jgrma.20.00085 |url-status=live }}</ref><ref name="uses">{{cite web|url=http://whc-oils.com/castor-oil.html|title=Multiple uses of castor oil|access-date=2007-08-02|archive-date=2007-09-29|archive-url=https://web.archive.org/web/20070929062813/http://whc-oils.com/castor-oil.html|url-status=dead}}</ref><ref>{{cite journal|title=Castor oil as a renewable resource for the chemical industry |date=2010-01-25 |doi=10.1002/ejlt.200900138 |volume=112 |journal=European Journal of Lipid Science and Technology |pages=10–30|last1 = Mutlu|first1 = Hatice|last2=Meier |first2=Michael A. R. }}</ref><ref>{{Cite journal|last=Ogunniyi |first=D.S. |date=June 2006 |title=Castor oil: A vital industrial raw material |journal=Bioresource Technology |volume=97 |issue=9 |pages=1086–91 |doi=10.1016/j.biortech.2005.03.028 |pmid=15919203 |bibcode=2006BiTec..97.1086O }}</ref> 
[[Transesterification]] followed by [[steam cracking]] gives [[undecylenic acid]], a precursor to specialized polymer [[nylon 11]], and [[heptanal]], a component in fragrances.<ref>Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, page 6162</ref> 
Breakdown of castor oil in strong base gives [[2-Octanol|2-octanol]], both a fragrance component and a specialized solvent, and the [[dicarboxylic acid]] [[sebacic acid]]. Hydrogenation of castor oil saturates the alkenes, giving a waxy lubricant.<ref name=ullmanns/> 
Castor oil may be epoxidized by reacting the OH groups with [[epichlorohydrin]] to make the [[Castor oil glycidyl ether|triglycidyl ether of castor oil]] which is useful in epoxy technology.<ref>{{Cite book|url=https://books.google.com/books?id=XiRdDgAAQBAJ&q=Heloxy+505&pg=PA157|title=Polymeric Thermosetting Compounds: Innovative Aspects of Their Formulation Technology|last=Hermansen|first=Ralph D.|date=2017-03-16|publisher=CRC Press|isbn=9781771883153|language=en|access-date=2020-11-09|archive-date=2023-01-14|archive-url=https://web.archive.org/web/20230114165300/https://books.google.com/books?id=XiRdDgAAQBAJ&q=Heloxy+505&pg=PA157|url-status=live}}</ref> 
This is available commercially as Heloxy 505.<ref>{{cite book |last1=Ash |first1=Michael |last2=Ash |first2=Irene |title=Handbook of fillers, extenders, and diluents |publisher=Synapse Information Resources |location=Endicott, NY |isbn=9781890595968 |page=82 |edition=2nd|year=2007 }}</ref>

The production of [[Lithium soap#Lithium grease|lithium grease]] consumes a significant amount of castor oil. [[Hydrogenation]] and [[saponification]] of castor oil yields 12-hydroxystearic acid, which is then reacted with [[lithium hydroxide]] or [[lithium carbonate]] to give high-performance lubricant grease.<ref>{{Cite book|title=Kirk-Othmer Encyclopedia of Chemical Technology |url=https://www.scribd.com/doc/30116043/Castor-Oil |access-date=2010-07-12 |url-status=dead |archive-url=https://web.archive.org/web/20110714101239/http://www.scribd.com/doc/30116043/Castor-Oil |archive-date=July 14, 2011 }}</ref>

Since it has a relatively high [[dielectric constant]] (4.7), highly refined and dried castor oil is sometimes used as a [[dielectric fluid]] within high-performance, high-voltage [[capacitor]]s.

===Lubrication===
[[File:Advertisement from The Aerial Age Weekly in 1921 - 002.jpg|thumb|Castor oil advertisement from ''The Aerial Age Weekly'' in 1921]]
Vegetable oils such as castor oil are typically unattractive alternatives to [[petroleum]]-derived [[lubricants]] because of their poor [[oxidation|oxidative]] stability.<ref>{{cite web |url= http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=166442 |title=Directed synthesis of base oils that overcome traditional vegetable oil shortcomings|author-first1=Terry|author-last1=Isbell|publisher=Society of Tribologists and Lubrication Engineers|date=May 20, 2004|access-date= 2007-08-02 |archive-date= 2006-10-01 |archive-url= https://web.archive.org/web/20061001013304/http://ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=166442 |url-status= live }}</ref><ref>{{cite web |url= http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/oil.html#Environment |title= Petroleum Oil and the Environment |publisher= DOE |access-date= 2006-12-28 |archive-date= 2009-08-23 |archive-url= https://web.archive.org/web/20090823080443/http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/oil.html#Environment |url-status= live }}</ref> Castor oil has better low-temperature [[viscosity]] properties and high-temperature lubrication than most vegetable oils, making it useful as a lubricant in [[Jet engine|jet]], [[Diesel engine|diesel]], and racing engines.<ref>{{cite web|last=McGuire |first=Nancy |title=Taming the Bean |publisher=The American Chemical Society |year=2004 |url=http://www.chemistry.org/portal/a/c/s/1/feature_pro.html?id=c373e9faf603d46b8f6a4fd8fe800100 |access-date=2007-08-02 |url-status=dead |archive-url=https://web.archive.org/web/20060927062935/http://www.chemistry.org/portal/a/c/s/1/feature_pro.html?id=c373e9faf603d46b8f6a4fd8fe800100 |archive-date=September 27, 2006 }}</ref> The viscosity of castor oil at 10&nbsp;°C is 2,420 [[centipoise]],<ref name=Mat_hand>{{cite book |last1= Brady |first1= George S. |title= Materials Handbook |year= 1997 |publisher= McGraw-Hill |location= New York |isbn= 978-0070070844 |edition= 14th |last2= Clauser |first2= Henry R. |last3= Vaccari |first3= John |url-access= registration |url= https://archive.org/details/materialshandboo14geor }}</ref> but it tends to form gums in a short time, so its usefulness is limited to engines that are regularly rebuilt, such as racing engines. Lubricant company [[Castrol]] took its name from castor oil.

Castor oil has been suggested as a lubricant for [[bicycle pump]]s because it does not degrade natural rubber seals.<ref>{{Cite book |last= Older |first= Jules |title= Backroad and Offroad Biking |publisher= Stackpole Books |location= Mechanicsburg, PA |year= 2000 |page= 37 |isbn= 978-0811731508}}</ref>

====Turkey red oil====
Turkey red oil, also called sulphonated (or sulfated) castor oil, is made by adding [[sulfuric acid]] to vegetable oils, most notably castor oil.<ref name=HP/> It was the first synthetic [[detergent]] after ordinary [[soap]]. It is used in formulating [[lubricant]]s, softeners, and [[dye|dyeing assistants]].<ref name=HP>{{cite book |last1=Penda |first1=H |title=Herbal Soaps & Detergents Handbook |date=2017 |publisher=NIIR |location=Delhi, India |isbn=9789381039007 |page=121}}</ref>

====Biodiesel====
Castor oil, like currently less expensive vegetable oils, can be used as feedstock in the production of [[biodiesel]]. The resulting fuel is superior for cold winters, because of its exceptionally low [[cloud point]] and [[pour point]].<ref>''Biodiesel from Castor Oil: A Promising Fuel for Cold Weather'' [http://www.icrepq.com/full-paper-icrep/222-barajas.pdf (PDF)] {{webarchive |url=https://web.archive.org/web/20130616073236/http://www.icrepq.com/full-paper-icrep/222-barajas.pdf |date=June 16, 2013 }} by Carmen Leonor Barajas Forero, 2004-10-12. Retrieved 2012-01-24.</ref>

Initiatives to grow more castor for energy production, in preference to other oil crops, are motivated by social considerations. Tropical subsistence farmers would gain a [[cash crop]].<ref>[http://www.biodieselmagazine.com/articles/622/the-promise-of-the-castor-bean ''The Promise of the Castor Bean''] {{webarchive |url=https://web.archive.org/web/20160309162746/http://www.biodieselmagazine.com/articles/622/the-promise-of-the-castor-bean |date=March 9, 2016 }} by Elizabeth Johnson, Biodiesel Magazine, 2004-12-01. Retrieved 2012-01-24.</ref>

===Early aviation and aeromodelling===
[[File:Le Rhone 9C.jpg|thumb|right|World War I aviation [[rotary engines]] used castor oil as a primary lubricant, mixed with the fuel]] 
Castor oil was the preferred lubricant for [[rotary engines]], such as the [[Gnome et Rhône|Gnome engine]] after that engine's widespread adoption for aviation in Europe in 1909. It was used almost universally in rotary-engined Allied aircraft in [[World War I]]. Germany had to make do with inferior ''[[ersatz]]'' oil for its rotary engines, which resulted in poor reliability.<ref>{{cite book |last= Guilmartin |first= John F. Jr. |title= Two Historians in Technology and War |year= 1994 |publisher= United States Army War College, Strategic Studies Institute |isbn= 978-1428915220 |page= 10 |chapter= Technology and Strategy: What Are the Limits?}}</ref><ref>{{cite book |last= Fisher |first= Suzanne Hayes |title= The European Powers in the First World War: An Encyclopedia |year= 1999 |publisher= Taylor & Francis |isbn= 978-0815333517 |page= 10 |chapter= Aircraft, production during the war |editor-first1= Spencer C. |editor-last1= Tucker |editor-first2= Laura Matysek |editor-last2= Wood |editor-first3= Justin D. |editor-last3= Murphy }}</ref><ref>{{cite book |title= Tariff Information Surveys on the Articles in Paragraphs 44 and 45 of the Tariff Act of 1913 |year= 1921 |author= U.S. Tariff Commission |page=40 |publisher= Government Printing Office |location= Washington, D.C. |author-link= United States Tariff Commission }}</ref>

The [[methanol]]-fueled, two-cycle, [[Glow plug (model engine)|glow-plug engines]] used for aeromodelling, since their adoption by [[model airplane]] hobbyists in the 1940s, have used varying percentages of castor oil as lubricants. It is highly resistant to degradation when the engine has its fuel-air mixture leaned for maximum engine speed. Gummy residues can still be a problem for aeromodelling powerplants lubricated with castor oil, however, usually requiring eventual replacement of [[ball bearing]]s when the residue accumulates within the engine's bearing races. One British manufacturer of [[sleeve valve]]d four-cycle model engines has stated the "varnish" created{{fact|date=January 2025}}<!-- many classical sources talk about the absence of film --> by using castor oil in small percentages can improve the pneumatic seal of the sleeve valve, improving such an engine's performance over time.

==Safety==
The castor seed contains [[ricin]], a toxic [[lectin]]. Heating during the oil extraction process denatures and deactivates the lectin. Harvesting castor beans, though, may not be without risk.<ref>{{Cite journal |last1=Auld |first1= DL |last2= Pinkerton |first2= SD |last3= Rolfe |first3= R |last4= Ghetie |first4= V |last5= Lauterbach |first5= BF |display-authors= 4 |title= Selection of castor for divergent concentrations of ricin and ricinus communis agglutinin |journal= Crop Science |volume= 39 |pages=353–7 |date= March–April 1999 |url=http://crop.scijournals.org/cgi/content/abstract/39/2/353 |archive-url= https://web.archive.org/web/20081012215450/http://crop.scijournals.org/cgi/content/abstract/39/2/353 |archive-date=2008-10-12 |doi=  10.2135/cropsci1999.0011183X003900020008x|access-date=2007-07-31 |issue=2}}</ref> The International Castor Oil Association FAQ document states that castor beans contain an allergenic compound called CB1A. This chemical is described as being virtually nontoxic, but has the capacity to affect people with hypersensitivity. The allergen may be neutralized by treatment with a variety of alkaline agents. The allergen is not present in the castor oil itself.<ref>{{cite web | last=Dierig | first=David A. | title=Lesquerella | work=New Crop FactSHEET | publisher=Center for New Crops & Plant Products, at Purdue University | year=1995 | url=http://www.hort.purdue.edu/newcrop/cropfactsheets/Lesquerella.html | access-date=2007-08-01 | archive-date=2007-10-25 | archive-url=https://web.archive.org/web/20071025022951/http://www.hort.purdue.edu/newcrop/cropfactsheets/Lesquerella.html | url-status=live }}</ref>

==See also==
* [[Botanol]], a flooring material derived from castor oil
* [[Castor wax]]
* [[List of unproven and disproven cancer treatments]]

==References==
{{Reflist|2}}

==Further reading==
* {{Kirk-Othmer|title=Castor Oil|last=Naughton |first=Frank|doi=10.1002/0471238961.0301192014012107.a01.pub2|mode=cs1|postscript=none}} – overview of chemical properties and manufacturing of castor oil

==External links==
{{Commons category}}
* {{ICSC|1452|14}}

{{Laxatives}}
{{fatsandoils}}
{{Authority control}}

{{DEFAULTSORT:Castor Oil}}
[[Category:Ayurvedic medicaments]]
[[Category:Castor oil plant]]
[[Category:Cosmetics chemicals]]
[[Category:Laxatives]]
[[Category:Liquid dielectrics]]
[[Category:Non-petroleum based lubricants]]
[[Category:Oils]]
[[Category:Traditional medicine]]
[[Category:Triglycerides]]