Castor oil is a vegetable oil that’s extracted from the seeds of the castor oil plant (Ricinus communis L.).
Castor seeds contain between 30%–50% oil, which is extracted from the beans by several methods, including mechanical pressing, solvent extraction, or a combination of the two.
Castor oil has a variety of applications in the chemical industry and is commonly used as an ingredient in products such as paints, coatings, inks, and lubricants.
It’s also an effective natural moisturizer and is used in the medical field as a laxative, in wound dressings, and as a drug delivery vehicle for certain medications.
Here’s what you need to know about castor oil, including its potential benefits, side effects, and safety.
Although castor oil is a type of vegetable oil, it’s not a culinary oil. It has a very thick and sticky texture and is high in compounds that make it unsafe to consume in high doses.
However, it does have medicinal and industrial uses.
Castor oil has been used as a natural medicine since ancient times and is still used worldwide today in folk medicine to treat conditions such as wounds, eye diseases, and rheumatic diseases.
It’s also FDA-approved for use as a stimulant laxative and is sometimes applied to the skin as a natural moisturizer.
It’s a Powerful Laxative
Although castor oil is often used to treat a variety of health conditions in traditional medicine and folk medicine systems, the FDA has only approved it for use in the U.S. as a stimulant laxative.
Stimulant laxatives work by stimulating nerves located in the gastrointestinal tract, which increases motility and intestinal secretions. This speeds up the movement of material through the intestines, which helps clear the bowels of stool.
Although stimulant laxatives are effective, they are powerful and are only meant to be used for short time periods and to relieve temporary constipation. For example, stimulant laxatives are sometimes used to clear the bowel before medical procedures such as colonoscopies.
After ingesting castor oil, digestive enzymes break it down into ricinoleic acid, which activates certain receptors found in intestinal smooth muscle cells that create movement in the intestines.
Research suggests that castor oil can be helpful for relieving certain types of short-term constipation. However, it’s not commonly used by practitioners in the U.S. because it’s much more likely to cause side effects, such as diarrhea, cramping, and pain, compared to other types of laxatives. For example, studies show that compared to senna, another type of stimulant laxative, castor oil is more likely to cause adverse side effects like abdominal cramping, bloating, vomiting, and dizziness. For these reasons, castor oil isn’t commonly recommended for the treatment of constipation in the U.S.
However, castor oil may be effective for cleansing the bowel before a noninvasive type of colonoscopy called a colon capsule endoscopy (CCE), which is a procedure that involves using a camera to examine the part of the large intestine called the colon.
A 2022 review of six studies found that the pooled capsule excretion rate in patients who received castor oil was 19% higher than in people who didn’t receive castor oil. That said, other laxatives are typically used for bowel cleansing, as castor oil is associated with a greater risk of side effects.
If you’re experiencing constipation, you shouldn’t use castor oil unless you’re being monitored by a healthcare provider. Using castor oil incorrectly or taking too high of a dose can lead to dangerous side effects, some of which could be life-threatening.
Has Moisturising Properties and May Promote Wound Healing
Castor oil is rich in fatty acids that are effective for softening the skin, which is why it’s used in natural beauty products such as skin moisturizers. Castor oil is considered an occlusive moisturizer, which is a type of moisturizer that prevents the evaporation of water from the skin or reduces water loss from the skin by forming a protective barrier. When you apply castor oil to the skin, it traps moisture inside, allowing the deeper layers of the skin to be replenished.
However, because castor oil is thick and sticky, it’s usually mixed with other oils, such as coconut oil, jojoba oil, and sweet almond oil, to create hydrating and natural skin treatments.
Castor oil has antimicrobial and anti-inflammatory properties, so it may offer benefits to people with inflammatory skin conditions. That said, there are currently no clinical studies investigating the effectiveness of castor oil as a skin moisturizer or in treating inflammatory skin diseases.
Castor oil may also be helpful in the treatment of wounds when combined with other ingredients. For example, castor oil is a main ingredient in Venelex, a topical dressing used to treat acute and chronic wounds and pressure ulcers.
In addition to castor oil, Venelex contains Peru balsam, which is a balm derived from the Myroxylon tree, and additives including glycerol monostearate. Castor oil helps create a moist environment that promotes healing and helps prevent wound cracking.
The ricinoleic acid found in castor oil has also been shown to have pain-relieving and anti-inflammatory properties, which also makes it an effective wound treatment.
However, although castor oil is used in certain wound treatments, it’s not recommended for home use in the treatment of wounds like cuts and burns.
May be Helpful for Certain Eye Conditions
Recent research suggests that castor oil may be an effective treatment for certain eye conditions, such as blepharitis. Blepharitis is an inflammatory condition that causes your eyelids to become red, itchy, swollen, and irritated. The condition is uncomfortable and can cause dandruff-like skin flakes to form on the eyelashes.
A 2021 study mentions that castor oil could help supplement deficient physiological tear film lipids, which could reduce tear evaporation and improve blepharitis symptoms.
A 2021 study that included 26 people with blepharitis found that the participants who were treated with castor oil, which involved applying 100% cold-pressed castor oil to the eyelids of one eye twice daily for four weeks, experienced significant improvements in ocular surface signs and blepharitis symptoms.
Castor oil is also an ingredient in eye drops used to treat dry eye, such as Restasis.
While castor oil may be helpful for treating certain eye conditions, you shouldn’t put castor oil directly into your eye. Castor oil should only be used to treat eye conditions by medical providers in a clinical setting.
Could Help Induce Labor in Clinical Settings
Castor oil has long been used as a natural way to induce labor. It stimulates the cervix by increasing the production of prostaglandins, a group of lipid compounds that play a central role in pregnancy and the induction of labor.
For example, prostaglandins mediate cervical ripening and stimulate uterine contractions.
A 2022 review of eight studies found that oral administration of castor oil is effective for cervical ripening and labor induction in pregnant women. The use of castor oil may help improve the chances of a healthy vaginal delivery and reduce the need for cesarean sections (c-sections).
Castor oil may be used by trained medical professionals, such as physicians and midwives, to induce labor. However, castor oil should never be used by pregnant women who aren’t under medical care as it can lead to dangerous pregnancy complications.
Castor oil is only recommended for oral use in the treatment of constipation. Even then, it’s best to take castor oil under the supervision of a healthcare provider, as it could cause side effects if misused.
You can also use castor oil topically as a natural moisturizer by blending it with other oils, such as coconut oil and sweet almond oil.
What’s more, studies also show that castor oil may be a helpful addition to denture storage solutions. Brushing and soaking dentures in castor oil-containing solutions has been shown to help reduce levels of Candida fungi, which commonly grow on dentures. If Candida builds up on dentures, it can trigger a condition called denture stomatitis, an infection that causes irritation, inflammation, and redness in the mouth.
If you’re interested in using castor oil to clean your dentures, talk to the healthcare provider who manages your oral health for tips on how to use it appropriately and safely.
Lastly, some people use castor oil as a moisturizing treatment for their hair. Although castor oil is used in hair care in many areas of the world, its sticky and thick texture could lead to a condition called acute hair felting in people with long, thick hair. Acute hair felting causes the hair to become severely matted. If hair felting is severe, the hair may have to be cut off.
Therefore, if you’re using castor oil for hair care, you must be extremely careful, especially if you have long hair.
Castor oil is only approved for oral use as a laxative and should ideally be taken under medical supervision to ensure safety.
Although it’s sometimes used orally for other purposes in medical settings, you should generally avoid consuming castor oil to treat any other health condition.
The typical dose for constipation treatment in medical settings is a dose of one to a maximum of four tablespoons in a single daily dose. Castor oil should never be given to children under the age of two years old.
When used appropriately, castor oil is considered safe. However, it can lead to serious health issues if too much is ingested. Plus, the compounds found in castor oil aren’t safe for certain populations.
For example, castor oil can cause serious digestive issues, such as diarrhea and vomiting, and even lead to severe electrolyte and acid-base imbalances if over-consumed.
It’s also unsafe for pregnant women to ingest any amount of castor oil unless it’s prescribed and monitored by a licensed healthcare provider, as it can induce labor.
When used topically, castor oil may also cause allergic reactions in some people. For this reason, if you’re interested in using castor oil as a natural skin treatment, it’s important to test it on a small area of your skin to see how you react.
Also, castor beans contain a toxic enzyme called ricin. However, castor oil is safe to consume because the extraction process deactivates ricin.
If using castor oil for laxative purposes, it’s recommended to take it two or more hours before or after taking any medications, as laxatives may affect how other drugs work.
Also, because castor oil is a powerful laxative, taking it alongside other laxatives could lead to significant gastrointestinal discomfort and serious health issues such as dehydration.
Castor oil products, such as capsules and liquids, can be purchased online and at natural food stores and pharmacies.
Medications that contain castor oil, such as bowel preparations and those used to treat dry eye, are prescribed by healthcare providers.
If you take more than the recommended one to four tablespoons of castor oil for the treatment of constipation, it can lead to unpleasant side effects such as vomiting, nausea, diarrhea, and stomach pain.
Because castor oil can cause side effects in high doses, it’s recommended to follow the advice of a healthcare provider if you’re using castor oil orally.
When taken orally, castor oil could lead to the following side effects:
- Diarrhea
- Vomiting
- Cramping
- Bloating
- Stomach pain
- Dizziness
When used on the hair and skin, castor oil could cause allergic reactions and may cause acute hair felting in people with thick hair.
Also, castor oil has the ability to induce labor, so it should be used for laxative purposes in pregnant women.
Castor oil is a vegetable oil derived from castor beans. It has a variety of uses in folk and traditional medicine systems but is currently only approved for use as a stimulant laxative by the FDA.
Some studies suggest that castor oil could be used to treat constipation, prepare the bowel for surgeries, treat certain eye diseases, induce labor in medical settings, and act as a natural skin moisturizer.
Although castor oil is generally considered safe, it’s recommended only to use castor oil orally when under medical supervision, as it can cause side effects, such as diarrhea and vomiting, especially when taken in high doses.
