Written by Karen Hovav, MD, FAAP | Reviewed by Christina Palmer, MD
Key takeaways:
Castor oil has been used for centuries in traditional medicine as a natural substance thought to have healing properties.
There is evidence that castor oil can help relieve constipation, induce labor, and soften skin. Some people use castor oil to promote hair growth, but the evidence is lacking.
Possible side effects of taking castor oil by mouth include stomach cramps and diarrhea. Since castor oil is used to induce labor, be sure to ask your healthcare provider before using it if you are pregnant.
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Castor oil is a type of vegetable oil that comes from the seeds of the castor or Ricinus communis plant. It’s thick in nature and has a clear to light-yellowish color.
Castor oil and other parts of the castor plant have been used for medicinal purposes since ancient times. Today, you will still hear claims about castor oil’s potential health benefits. While some castor oil benefits have stood the test of time, others don’t hold up when we look at the evidence.
What are the benefits of castor oil?
Here’s a rundown of the current science on castor oil’s potential benefits.
Relieves constipation
Castor oil is most well-known as a way to relieve constipation. The FDA considers castor oil to be a generally safe and effective laxative. It has even been studied as a potential treatment to clean out the bowels before a colon cancer screening.
But using castor oil as a laxative is not as common today. It can have a lot of side effects, such as stomach cramping and vomiting. And there are many other laxatives available — like sennosides — that are more effective and have fewer side effects.
May induce labor
Some research suggests castor oil may be an effective way to start the labor process. But existing research on castor oil’s ability to induce labor may be too limited and flawed to say for sure whether it works. Scientists also suggest that the side effects may outweigh the potential benefits of castor oil.
Supports skin health
Castor oil may provide some general skin benefits, such as softening and moisturizing skin. Beyond that, it’s unclear whether castor oil can help manage skin conditions. But researchers are looking into castor oil as a possible treatment for psoriasis, acne, and wound healing.
Boosts hair health
Some people use castor oil as a natural remedy for hair growth. But there is no evidence that using it leads to hair growth. That said, castor oil has antibacterial and anti-inflammatory properties and can help create a healthy scalp microbiome for your hair follicles.
Castor oil has also been shown to help moisturize hair and improve luster or shine. But a note of caution: It may cause oil buildup on the scalp or irritate your skin. For example, if castor oil from your hair gets on your pillowcase, it could cause acne on your face.
What are some side effects of castor oil?
Castor oil can have significant side effects when taken by mouth, most of which affect your digestive system. Some possible castor oil side effects include:
Diarrhea
Nausea
Vomiting
Stomach cramps
Dizziness
Dehydration
Electrolyte imbalance (which can lead to confusion or sleepiness)
Who should not take castor oil?
Castor oil is safe for most people. But it can cause unwanted side effects and reactions in others. People who should avoid taking castor oil include:
Pregnant people
People with electrolyte imbalances, such as those with kidney disease or who are taking certain medications
People with inflammatory bowel disease
Anyone with severe abdominal pain that could be caused by serious issues like appendicitis or bowel obstruction
How do you use castor oil?
How you take castor oil depends on what you’re using it for. Castor oil can be taken by mouth or applied topically.
By mouth
Castor oil for constipation is usually taken by mouth. The recommended dose for adults and children older than 12 years is 15 mL to 60 mL once daily. Lower doses are less likely to cause side effects. Castor oil tends to work pretty quickly. Generally, you can expect to have a bowel movement within 6 to 12 hours after taking castor oil.
Experts recommend limiting daily use to 1 week. Overuse can lead to serious side effects or complications. If you’re taking any medications, talk to your healthcare provider before trying castor oil for constipation.
When taken by mouth, 100% castor oil is recommended. This ensures the product is free of other chemicals. Since castor oil has an unpleasant taste, you can try mixing it with a cup of juice to mask the flavor.
Topically
Castor oil can also be applied topically on the hair or skin. People may use it to make their hair shiny or moisturize their skin. For example, you could use a castor oil pack –– a piece of fabric that has been soaked in the oil –– and apply it directly to a dry, chapped patch of skin.
The bottom line
Castor oil is a vegetable oil that has been used as a medicinal treatment as far back as ancient times. Today, people often use it as a natural remedy to promote hair growth or treat skin concerns. But there is limited evidence to support many of these benefits. Some studies suggest that when taken orally, castor oil can help relieve constipation. Topical use may help moisturize your hair or skin.
While it is safe for most people, it’s worth noting that castor oil may cause side effects like diarrhea and digestive upset. It’s best to talk to your healthcare provider before using castor oil.
References
Al-Mamun, M. A., et al. (2016). Characterization and evaluation of antibacterial and antiproliferative activities of crude protein extracts isolated from the seed of Ricinus communis in Bangladesh. BMC Complementary Medicine and Therapies.
Alookaran, J., et al. (2022). Castor oil. StatPearls.
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