Wednesday Feb 21, 2024


What is Castor Oil?

Castor oil is a type of vegetable oil derived from the seeds of the castor oil plant (Ricinus communis), which is also known as castorbean. In Latin, it is referred to as “palma Christi”, or “Palm of Christ”. Castor oil plants grow easily and are commonly found in tropical regions; they originated from the south-eastern Mediterranean Basin, Eastern Africa, and India. Most variants of the castor oil plant are bred commercially for increased oil production, while others are cultivated for their aesthetic qualities, as they can serve as an ornamental garden plant in zones with milder climates.

The colour of castor oil ranges from colourless to a very pale amber, or in some cases a pale greenish-yellow. It has a distinct taste and odour once first ingested, both of which are generally found to be unpleasant – the taste of castor oil has been compared to that of lipstick, or petroleum jelly; and it has waxy, oily odour. Jamaican black castor oil, which is a less common variation, is a dark brown to black in colour and has a smoky odour which has been compared to ashes. The undesirable smell of castor oil is commonly masked by mixing it with other fragrant essential oils; chilling and flavouring with orange juice or peppermint is sometimes used to mask its nauseating taste.

Castor oil is relatively viscous compared to cooking oil, being almost syrupy in consistency. It has a high density and boiling point, and does not dry easily in air – these properties make it popular for both medicinal and industrial use.


How is Castor Oil Made?

Castor oil is made using what is known as the ‘cold press’ method. While technological advancements nowadays may make the process much easier, the traditional method of producing castor oil was tedious and required significant effort. Firstly, clusters of spiky green ‘fruit’ are harvested from the castor oil plants, then sun-dried and shelled. This allows the seeds of the plant, otherwise known as the castor “beans” to be collected. They are brown, speckled and look similar to nuts. The castor seeds are then roasted dry before being ground into a fine paste using a mortar and pestle. This process may take many hours depending on the amount of castor beans used. The resulting paste is added to boiling water and left to simmer, until emulsification of oil from the paste occurs. The oil is then filtered and left to cool overnight before packaging. The price of castor oil varies greatly depending on its quality and purity.

Harvesting castor oil poses a small amount of risk to the involved workers. The castor plant contains a toxic protein called ricin, which is generated as a by-product of castor oil extraction. It can cause a myriad of inflammatory symptoms, including and up to death, depending on its route of exposure and the dosage received. Ricin is deactivated and discarded with the residual paste following the boiling process, hence the exposure rate to ricin is relatively low, unless the seed is chewed directly. However, there are also allergenic compounds found on the plant surface, such as the on the spiky shells, that can possibly result in nerve damage. To counteract these health issues, there is an ongoing quest for a safe castor oil substitute, and genetic modification of the castor oil plant to prevent ricin synthesis is being researched.


History of Castor Oil

The term “castor”, from which the plant gets its name, means ‘beaver’ in Latin. Thus, it has been theorized that the name “castor oil” originated from its use as a cheaper alternative to castoreum, which is a perfume base made from the dried perineal glands of the beaver. Another theory suggests that English traders named the plant “castor” after confusing its oil with that of a different plant called castus. The scientific name Ricinus communis was coined by Carolus Linnaeus in the eighteenth century, translating directly to “common tick”, as Linnaeus found the castor bean to resemble a blood-engorged tick, and the plant is commonly found in the area as a weed due to its ease of growth.

The medical applications of castor oil are by no means a recent discovery, having been widely used in its lands of origin in earlier times, allegedly as an elixir for general health and wellbeing. The venerable Ayurvedic healing practices of India incorporate castor oil in many of their remedies, and the same oil is regarded as a cure-all for various infectious diseases and chronic health conditions in Asia and Africa. The use of castor oil by mankind can be dated back to ancient Egyptian times, as indicated by the discovery of ceremonially-included castor beans within Egyptian tombs that date back to 4000BC. The Ebers Papyrus, an Egyptian medical text from 1500BC, details the use of castor oil by Egyptian physicians as a method to protect against eye irritation.

Traditionally, castor oil was (and still is, in some cases) used to induce labour in pregnant women, as castor oil is known to cause contractions. Despite being a generally accepted fact, however, concrete scientific evidence has yet to found which directly links the effects of the oil to the birthing process. Castor oil has also been used as a component of early facial masks, and as fuel for wick lamps.

The industrial value of castor oil was also recognized and put to use very early on in time. The Wakefield Oil Company, now better known as Castrol, was founded by Charles Cheers Wakefield in 1899. The company is a British global brand which supplies a wide range of industrial and automotive lubricants, and was christened with the new brand name “Castrol” following research and inclusion of castor oil in their lubricant formulations. During World War I, castor oil was utilized as a lubricant in aircraft, as it was one of the best options compared to other oils available at the time. It was suggested that the main reason pilots in World War I wore scarves around their faces while flying was to minimize inhalation of fumes emitted from the hot oil.

Castor oil, interestingly enough, was also used as a tool to exact punishment from individuals using minimal effort. As can be seen in animated cartoons such as Tom and Jerry, the individual is force-fed castor oil and then left to suffer through its effects, implied as merely nausea from the nasty taste. However, a laxative effect often also takes place, the severity of which increases with the amount of castor oil consumed. This then results in discomfort and humiliation of the recipient, especially if access to bathroom facilities is denied. The most famous case(s) of using of castor oil for such a purpose was in Fascist Italy under the command of Benito Mussolini. Members of the political opposition were force-fed large amounts of the oil, resulting in severe diarrhoea and subsequent dehydration. These treatments were sometimes fatal when paired with nightstick beating, as the dehydration resulting from excessive diarrhoea complicated their recovery from the injuries.

As a result, it is said that “the bludgeon and castor oil” played a major role in backing Mussolini’s power and standing. Less extreme cases involved using castor oil in smaller quantities to intimidate the people, acting as a means to dissuade them from disloyalty or shirking their duties. The Italian terms for “the use of the bludgeon” and “the use of castor oil” are used in political satire to convey the meaning of “to coerce or abuse”, and still carry strong political connotations to this day.

Uses of Castor Oil in Health

  1. Laxative

Castor oil is most famous for its laxative qualities when taken internally in small amounts, and has been touted as a detoxifying agent for being able to completely clear out one’s bowels and intestines. The usual dose for a healthy adult is one teaspoon a day, and it is not recommended for children below the age of 5, as they are generally discouraged from consuming laxatives altogether. It should not be consumed for more than 7 days continuously unless prescribed by a doctor. Castor oil is a form of contact laxative, which induces contractions in the intestinal walls by acting as a mild irritant. These increased contractions then move along the stool mass, encouraging bowel movements. As such, it can be used to accelerate recovery from food poisoning cases. There is a side effect of nausea following consumption of the oil, most likely due to its unpleasant taste, thus it is no longer commonly used due to the availability of gentler and safer alternatives.


  1. Induce labour

Expecting women are discouraged from consuming castor oil for its laxative effect, as it is known for being able to induce contractions, and may lead to complications in the pregnancy. It has been traditionally given to women who have completed the full term of their pregnancy in order to stimulate the birth process.


  1. Lotion

Castor oil has a greater variety of external uses, and is safer to use this way compared to by consumption, as it is relatively hypoallergenic and unlikely to cause any issues to skin. The moisturising qualities of the oil makes it effective in alleviating dry skin, dermatitis and sunburns, and it is long lasting as it resists washing or drying. It can also be applied to cuticles as a remedy for dry and brittle nails. Castor oil is quite similar to petroleum jelly in this regard, the difference being that that the oil is much smoother and results in less of a mess. To remove corns and warts, castor oil can be used to soak and soften them before removal using a pumice stone.


  1. Antimicrobial agent

Castor oil contains ricinoleic acid, which is an uncommon form of fatty acid found only in castor beans and a type of fungus known as ergot. This fatty acid inhibits the growth of many types of microbes, including bacteria, viruses, and fungi. This gives castor oil an antiseptic quality when applied directly to areas of inflammation or infection. It can be used to diminish acne, as well as other skin conditions like fungal infections, keratosis, scars, abscesses, open sores and haemorrhoids by disinfecting the skin. The oil can be dabbed over the affected area using a cotton ball, or for longer-lasting treatments, the cotton ball can be taped in place to ensure the area remains soaked.


  1. Massage Oil

The superbly lubricating qualities of castor oil makes it suitable for use as a massage oil, and has the added effect of being able to stimulate the body’s immune and lymphatic system, as the oil can penetrate the skin deeply. Research has shown that the body’s production of lymphocytes increases following exposure to castor oil; lymph circulation and drainage subsequently improves as well. To treat colic, massaging the baby’s stomach gently with castor oil can help them to pass gas and sleep better.


  1. Castor Oil Packs

As an alternative to massage, castor oil packs are commonly used in conjunction with heating pads to relieve menstrual cramps, arthritis, and muscle aches. To create your own castor oil pack, all that needs to be done is to soak a piece of thin fabric in castor oil, and lay it flat on the affected area. The soaked fabric should then secured with cling wrap, and kept warm by laying a heating pad or hot water bottle over it. This treatment method has been shown to ease uterine fibroids and shrink ovarian cysts.


  1. Hair tonics

Castor oil can function to prevent and remedy hair loss, and is applied by massaging it directly into the scalp. This is due to its antibacterial and antifungal properties, which allows it to counter folliculitis, dandruff and scalp infections. The ricinoleic acid present in castor oil has also been claimed to help balance scalp pH and thus replenish the scalp’s natural oils. The high density and moisturising qualities of castor oil makes it an excellent hair conditioner, preventing split ends and supporting the keratin in hair, making it stronger, smoother and less frizzy. Omega-6 and Omega-9 fatty acids found in castor oil also functions in promoting hair growth.


  1. Drug and cosmetic stabilizer

Castor oil is an inactive component of certain drugs, where its physical qualities come into play. In such cases, castor oil is used as an emulsifier, to make oils and other water-insoluble substances soluble. Hydrogenation produces another, heavier form of castor oil known as castor wax, which is commonly used in pills and tablets – it functions as an extended release agent, stiffening agent, and lubricant to ease consumption of the tablet or capsule. Tylenol (paracetamol) is one such example of a drug utilizing castor oil as an inactive ingredient.


Derivatives of ricinoleate, which is a substance formed from castor oil, act as stabilizers for a variety of common cosmetic products such as deodorant sticks, lipsticks, eyeliners, and soaps. This is because the derivatives are highly stable at both high and low temperatures, helping the cosmetic products maintain their smooth consistency regardless of different climate conditions.


  1. Possible cancer treatment

While ricin (the toxin found in, and sourced from castorbeans) is potentially fatal to humans, it is currently being researched for prospective use in cancer treatment. There is a possibility that with the right modifications, the toxic effects of ricin could be redirected to specifically target tumours. Ideally, it would kill only cancerous cells and not the healthy cells surrounding it, which is the greatest predicament faced by medical practitioners in present-day cancer treatment.


  1. Oral Contraceptive

Hulled castor seeds (with the shells removed) have been traditionally used as a birth control agent in some Nigerian tribes. While not scientifically proven, it has been claimed that a single dose of castor seeds taken orally is able to function as a contraceptive for up to 8-12 months.


Other Uses of Castor Oil

Castor oil is one of the first vegetable oils to be introduced for industrial purposes, where mineral oils previously dominated. It was able to make the cut because castor oil and its derivatives are highly viscous, physically stable, and possess superior lubricating qualities. This makes them valuable for use in automotives and various types of machinery as lubricants, hydraulic and brake fluids, and protective coatings. Castor oil is a main component in the motor oil of high-performance automobile and motorcycle engines, which are used for racing purposes; it is also used as a fuel additive for two-cycle engines.

The uses of castor oil in industrial settings are not restricted to heavy machinery alone – it is used in the production of many synthetic materials such as nylon and synthetic resins as a primary raw material. It is also used in products such as paints, varnish, dyes and inks, and serves as a coating for fabric and other materials in the form of waxes and polishes. Other industrial products utilizing castor oil include various insecticidal oils, and castor is even used in perfumes, being the source of several synthetic flower and fruit scents.

Castor oil is currently a candidate for future use as biodiesel, as its overall characteristics match up reasonably well with the requirements for a good biodiesel. The issue currently being investigated is the viscosity of castor oil, which is on the high side and may affect its performance. Currently, it appears that the viscosity of castor oil is within a suitable range, and it is highly likely that it may soon join the ranks of rapeseed oil and soybean oil as a biodiesel, as it is relatively cheap and easy to cultivate.





  1. This is one of the great reasons why I need to buy my own castor oil.

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