Castor Oil

Castor Oil

Castor oil has been used by humans for a variety of purposes for thousands of years. Its use continues to be widespread and it is employed in an equally diverse number of roles. From home remedies to modern medications, in lubricants and plastics, and as a food product or additive, the list of castor oil applications is extensive. The chocolate bar you eat today may contain a castor oil derivative in the packaging as well as the food itself. The following article will discuss the castor plant, its processing and refining, and many of the modern uses of castor oil.



Castor oil is processed from the seed (usually referred to as a castor bean) of the castor plant. The castor plant is native to the Mediterranean basin. It is most commonly cultivated in tropical regions. India, China and Brazil are the world’s largest producers of castor oil seed, with India accounting for nearly 70% of global production in 2008. Many varieties have been developed, including strains that are currently grown in Texas.

Castor oil seeds contain a high quantity of ricin, a poison which can be fatal in humans. While processing removes the danger of ricin, a fatal dose of crushed or chewed castor seeds is relatively small, usually requiring just four to eight seeds. For this reason cultivation can be seen as a dangerous job, and effort has gone in to developing strains with less toxicity.


Castor plant seeds are usually processed using a press. Seeds are first hulled and then fed into the hydraulic press. Oil is separated and the remaining material is fed back into the processing press. Typical high temperature presses can extract 80% of available oil. Further processing is achieved through hydrogenation and oxidation, among other methods, and is used to create castor oil derivatives.


Historical Use

Castor oil use by humans dates back to ancient Egypt where the oil was commonly used in lamps. Ancient texts describe the use of castor oil as a laxative. It has also been used as an antiseptic, a topical pain reliever, and as a dressing to treat any number of ailments. During Benito Mussolini’s Italian rule in World War II, castor oil was force fed to the dictator’s enemies. Castor oil overdose causes severe gastrointestinal discomfort and purging. Death can result from dehydration, which is a result of continuous diarrhea.

Modern Medications

Today, castor oil continues to be available over the counter for use as a laxative. While it is considered safe for this application, it is not a popular remedy for constipation as it can cause uncomfortable to severe cramping and uncontrollable, explosive diarrhea. More modern and readily available treatment options have replaced castor oil as a common and popular laxative.

However, castor oil continues to play a part in up to date medical procedures and treatments. Many of its derivatives are used in conjunction with other medications including use as an immune-stimulant in treatment of HIV/AIDS. Research continues into the possible use of castor plant by-products for the treatment of multiple sclerosis, liver disease and Parkinson’s disease. More studies need to be done to fully explore and explain the potential medical benefits of castor oil.


As the brand name Castrol suggests, castor oil is used as a lubricant for a variety of purposes. Among vegetable oils, castor oil is known for its relatively high viscosity. However, as castor oil also has the drawback of producing a good deal of gum build up, its use is limited to fairly specific roles. Castor oil is a popular model engine lubricant, and is also used in vehicle engines that are frequently rebuilt, such as drag racing engines. Except in certain niche applications, castor oil has for the most part been replaced by other oils as an engine lubricant.


Castor oil can be processed to produce ingredients that are used in many common plastics. Producing plastics from plant-based materials has the added benefit of potentially reducing the stress on fossil fuels caused by their use in the plastics industry.

Food Products

As mentioned above, castor oil is viewed as safe – aside from the potentially uncomfortable side effects – for human consumption. Castor oil can be used as a food additive, and in certain derivatives to flavor food. Furthermore, castor oil can be used as a preservative. In Asia, the oil is applied directly to grains like wheat and rice. This coating acts to preserve the food and acts as an anti-fungal agent.

Castor oil has a wide variety of beneficial uses, not the least of which is its potential to provide alternatives to products currently made from limited fossil fuel resources. Through millennia of human use, castor oil has been used for constantly evolving purposes. The oil continues to provide new benefits and unique possibilities in its diversity of applications.