What Is Castor Oil?

Used for Hair Health, Arthritis, Skin Health, and More

Castor oil is a natural remedy derived from the castor bean, known as Ricinus communis. The main component of castor oil is ricinoleic acid, a type of fatty acid shown to possess anti-inflammatory properties.

Long used in traditional medicine, castor oil is sometimes taken orally as a laxative, used topically to stimulate hair growth, or applied as a skin lubricant. Some people use castor oil to induce labor in pregnancy or to ease arthritis.

As exciting as these prospects may sound, keep in mind that science has a long way to go in verifying the benefits of castor oil. You should always consult a healthcare provider before using it.

This article explains the wide-ranging and purported benefits of castor oil. It also describes its possible side effects and why it's so important to use it only after consulting your healthcare provider.

Castor bean plant
w-ings / Getty Images

What Is Castor Oil Used For?

The research on the potential benefits of castor oil is limited. Furthermore, study results regarding its health effects have been inconsistent.

Here's what is known so far about some of castor oil's most popular uses:


It's long been claimed that castor oil can induce labor. But studies investigating this effect have yielded mixed results. A small study published in 2006 showed that pregnant women at term had an increased rate of labor in the first 24 hours after ingesting the oil. However, study authors recommended further investigation to confirm the benefit.

Later studies involved larger groups of women. A 2009 study involved 612 women whose pregnancies lasted longer than 40 weeks. Of these women, 205 received castor oil for induction of labor. The study's authors found that the time to birth was not significantly different between those who took the oil and those who did not.


The most common way to use castor oil as a laxative is to take it orally. (Prepare for its nasty taste, which might be described as moldy soap.)

If you aren't following instructions from your healthcare provider, then follow the directions on the label of the bottle. And use a specially marked spoon as you measure each dose.

A castor oil pack may work as an alternative for constipation. In one 2011 study, older patients with constipation found relief from symptoms (such as straining) after seven days of treatment.

Created by soaking a cloth in castor oil and then placed on the skin, castor oil packs are also thought to enhance circulation and promote healing of the tissues and organs underneath the skin.

Some alternative medicine practitioners use castor oil packs to improve liver function, relieve pain, reduce inflammation, and improve digestion.


To date, there is no evidence that castor oil can stimulate hair growth. However, preliminary research published in the Journal of Cosmetic Science in 2003 indicates that castor oil may improve the appearance of hair by increasing its luster.

Indeed, some people use castor oil as a hair conditioner. Others use it to prevent or treat dandruff.


Taking a castor oil supplement may be of some benefit to people with osteoarthritis of the knee, a 2009 study from Phytotherapy Research suggests.

For four weeks, 50 men and women with knee osteoarthritis (age 40 and up) took capsules containing either castor oil or diclofenac sodium (a nonsteroidal anti-inflammatory drug) three times daily for four weeks.

The results indicated that both treatments were effective at relieving pain associated with osteoarthritis. In the diclofenac sodium group, 90% (45 participants) showed significant improvement in pain levels; in the castor oil group, 92% (46 participants) showed significant improvement.

Study authors note that the findings are important because no side effects were associated with the use of castor oil. The same wasn't true with diclofenac sodium: About 20% of the patients complained of mild gastritis and 4% complained of skin rashes.

Skin Health

Many people use castor oil as a moisturizer, to reduce wrinkles, and improve skin quality.

While other plant oils (such as argan oil and avocado oil) have been investigated for these benefits, castor oil has not. Some people believe that since other plant oils boost skin health, then castor oil should be able to do so as well.

As logical as this theory sounds, it hasn't been confirmed through scientific evidence.

Other Uses

In addition to the studied uses of castor oil, the product is widely used for other purported benefits. Proponents claim that castor oil can treat a variety of conditions including:

Remember that there is not enough scientific evidence to know if castor oil is safe or effective for the treatment of any of these conditions.

Possible Side Effects

Swallowing too much castor oil can be harmful, according to the National Institutes of Health (NIH). Castor oil might cause fluid and potassium loss from the body when used for more than a week or in doses of more than 15 to 60 milliliters per day. (To put these numbers in perspective, 15 milliliters equals about 3 teaspoons.)

Signs of castor oil "overdose," which warrants immediate medical attention, include:

  • Abdominal cramps
  • Diarrhea
  • Dizziness
  • Fainting
  • Hallucinations
  • Nausea
  • Shortness of breath and chest pain
  • Throat tightness

Some people develop a rash when using castor oil on the skin. In addition, there is limited evidence that using castor oil on hair may be unsafe.

One study discovered a rare hair condition called "acute hair felting," where the hair becomes hard, twisted, and entangled. These symptoms occurred following the use of castor oil for the first time by healthy individuals.

Women who are pregnant should consult their healthcare provider before consuming castor oil. Parents of children should consult their pediatrician before giving castor oil to their child.

Safety Warning

Consuming a whole castor seed is unsafe. The outer coating (hull) of the castor seed contains a deadly poison that may cause nausea, vomiting, diarrhea, abdominal pain, dehydration, shock, and even death.

Dosage and Preparation

There are no official recommendations for the proper dosage of castor oil. Some over-the-counter brands recommend taking 15 milliliters a day if you're using it as a laxative. But this dosage may be too strong for an adult, not to mention a child.

Since the side effects are capable of sidelining you, it makes sense to check with your healthcare provider for advice before taking even a small dose of castor oil. And there is always the chance that the oil could interact with other medications you're taking.

What to Look For

Castor oil can be found in drugstores, natural foods stores, and stores specializing in dietary supplements. And like most products, castor oil can be purchased online.

Choosing the best castor oil is important. Experts recommend that you look for a reputable brand and, if possible, buy from a familiar vendor such as your local pharmacy.

To get a product that is pure, try to choose an organic castor oil. And read the label carefully. Added ingredients—such as fragrance or less expensive oils—may cause skin irritation.

Some people prefer cold-pressed castor oil because the oil's natural properties remain intact. Unrefined castor oil is also available for those who prefer even less processing.

Store castor oil in a cool, dark place, away from sunlight. If it starts to smell foul, it has gone bad and should be thrown away.

The Ricin Factor

Ricin is a potent toxin derived from part of the waste mash produced when beans from the castor plant are processed to make castor oil. Ricin is contained in the hull of the bean, which is discarded in the oil manufacturing process. This means it does not make its way into the end product.

Ricin made news when letters containing the toxin were sent to members of Congress and the White House in 2018. According to the Centers for Disease Control and Prevention (CDC), unintentional exposure to ricin is highly unlikely, except through the ingestion of castor beans. However, if you suspect exposure to ricin, the agency recommends that you seek medical help immediately.


Many people associate castor oil with being a cure for constipation, but it has other potential uses, such as inducing labor, relieving arthritis pain, and improving skin. Most of its claimed benefits aren't supported by much evidence, however.

Castor oil supplements can cause side effects such as diarrhea, abdominal cramps, nausea, and even fainting and hallucinations. Topical use can trigger a rash. Don't use it if you are pregnant or give it to a child without consulting a healthcare provider first.

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10 Sources
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