By Dr. Mercola
You are probably aware that castor oil is regarded by some as a remedy for constipation remedy.
But you may not be aware of its reported use as an antiviral, antibacterial, and antifungal, or that it has been used topically to treat a variety of skin conditions, reduce pain, and stimulate your immune system.
Read on, because I'm about to explore the myth and mystery of this unusual oil, and of course, investigate what modern science has to say about it.
However, regardless of what some of the research has suggested, you should be very cautious when experimenting with castor oil since the science is sparse at best, and there are several known reports of unpleasant side effects experienced by some users.
History of the Castor Seed: Ricinus Communis
Castor oil comes from the castor seed1, Ricinus communis, which has a very unusual chemical composition. Castor oil is a triglyceride, comprised of fatty acids, 90 percent of which is ricinoleic acid.
This unique fatty acid is found in lower concentrations in a few other seeds and oils (0.27 percent in cottonseed oil and 0.03 percent in soybean oil2) and is thought to be responsible for castor oil's unique healing properties. The castor seed plant is native to India.
Centuries ago, the plant was referred to as "Palma Christe" because the leaves were said to resemble the hand of Christ. This association likely arose out of people's reverence for the plant's healing abilities.
It was later adopted for medicinal use in Ancient Egypt, China, Persia, Africa, Greece, Rome, and eventually in 17th Century Europe and the Americas. Castor oil is now widely used in industry. The stem of the plant is used in the textile industry, particularly in Russia, where castor oil is known as "Kastorka."
The oil has a very consistent viscosity and won't freeze, which makes it ideal for lubricating equipment in severely cold climates. Modern non-medicinal uses for castor oil include:
- Food additive and flavoring agent
- Mold inhibitor
- Ingredient in skin care products and cosmetics (lipstick, shampoo, soap, and others)
- Used in the manufacturing of plastics, rubbers, synthetic resins, fibers, paints, varnishes, lubricants, sealants, dyes, and leather treatments; the lubricants company Castrol took its name from castor oil
Castor oil was first used as an aircraft lubricant in World War I. So, castor oil has a number of handy industrial uses. But did you know that the castor seeds from which castor oil is made can be DEADLY?
Part of the Castor Seed Heals—But Another Part Kills!
The potent toxin ricin3 is made from a protein in the castor seeds that, if ingested (orally, nasally, or injected), gets into the ribosomes of your cells where it prevents protein synthesis, which kills the cells. Ricin is made from the "mash" that is left over after processing castor seeds into oil.
Just 1 milligram of ricin is fatal if inhaled or ingested, and much less than that if injected. Eating just 5 to 10 castor seeds would be fatal.
Once poisoned, there's no antidote, which is why ricin has been used as a chemical warfare agent. Even though such a toxic component is also derived from this seed, castor oil isn't considered dangerous.
According to the International Journal of Toxicology's Final Report on Castor Oil4 , you don't have to worry about castor oil being contaminated by ricin, because ricin does not "partition" into the castor oil. Castor oil has been added to cosmetic products for many years, without incident. For example, castor oil and hydrogenated castor oil were reportedly used in 769 and 202 cosmetic products, respectively, in 2002.
The U.S. FDA gives castor oil a "thumbs up," deeming it "generally regarded as safe and effective" for use as a stimulant laxative.
The Joint Food and Agriculture Organization (FAO)/World Health Organization (WHO) Expert Committee on Food Additives has established an acceptable daily castor oil intake of up to 0.7 mg/kg body weight. This amounts to, roughly, one tablespoon for adults and one teaspoon for children. Taking castor oil orally usually results in a "purging" of the digestive tract in about four to six hours.
According to the International Castor Oil Association 5, castor oil studies in which people were dosed with castor oil at dietary concentrations as high as 10 percent for 90 days did not produce any ill effects.
In spite of the fact that U.S. FDA and the International Castor Oil Association have pronounced castor oil to be safe, if you are going to try it, as I've mentioned previously, proceed with extreme caution because a number of negative side effects have been reported.
Castor Oil is NOT without Side Effects
Castor oil's main side effects fall into the categories of skin reactions and gastrointestinal upset, which isn't terribly surprising given the agent's actions on your intestinal wall.6
Castor oil is broken down by your small intestine into ricinoleic acid, which acts as an irritant to your intestinal lining.
This effect is what gives castor oil the ability to reverse constipation—but it's also the reason that some people report digestive discomfort, diarrhea, and other gastrointestinal side effects.
If you suffer from cramps, irritable bowel, ulcers, diverticulitis, hemorrhoids, colitis, prolapses, or have recently undergone surgery, you should probably avoid castor oil due to these possible adverse reactions.
Although castor oil has been traditionally used to help stimulate labor in healthy pregnant women, there are widespread reports of nausea, including one study in 20017 that found nausea to be almost universally experienced by these women.
A Home Remedy that's Survived for Millennia
Adverse effects notwithstanding, Indians would traditionally boil seed kernels or hulls in milk and water, and then consume the brew to relieve arthritis, lower back pain, and sciatica. According to Williams' article8, castor seed plants are widely used in India for all sorts of medical problems, including the following:
- Inflammatory bowel disease
- Bladder and vaginal infections
Canary Islanders made poultices from the leaves of the castor plant to treat gynecological problems. Nursing mothers applied these poultices to their breasts to increase milk secretion and relieve inflammation of their mammary glands, and applied the poultice to their abdomens to promote normal menstruation. The topical absorption of castor oil is the basis for more modern "castor oil packs," which I'll be discussing later in detail.
Modern Medicinal Uses for Castor Oil
In general, the reported medicinal uses of castor oil fall into the following five general categories:
- Gastrointestinal remedy
- Antimicrobial (antibacterial, antiviral, and antifungal)
- Labor stimulant9
- Anti-inflammatory and analgesic
- Immune system and lymphatic stimulant
The oil's benefits can be derived by topical application, and it appears to be useful for a variety of skin conditions like keratosis, dermatosis, wound healing, acne, ringworm, warts and other skin infections, sebaceous cysts, itching, and even hair loss. Castor oil and ricinoleic acid also enhance the absorption of other agents across your skin. And castor oil shows some promise in the treatment of cancer. According to the American Cancer Society10 :
"Oncologists now use castor oil as a vehicle for delivering some chemotherapy drugs to cancerous tumors. A special formula of castor oil called Cremophor EL is used as a carrier for paclitaxel, a drug used to treat metastatic breast cancer and other tumors. Unfortunately, the vehicle sometimes causes problems of its own, including allergic reactions. This has prompted a search for substitute carriers."
They also report that early clinical trials suggest that ricin, when combined with an antibody to confine this poison to malignant cells, shrinks tumors in lymphoma patients. In fact, castor oil has been reportedly used to treat all of the following conditions listed below. While I certainly cannot attest to castor oil's efficacy for all of these conditions (as there is not enough research to date), I list them here as a way to illustrate the wide array of possibilities.
✓ Multiple sclerosis
✓ Parkinson's Disease
✓ Cerebral Palsy
✓ Migraine and other headaches
✓ Cholecystitis (inflamed gallbladder)
✓ Liver ailments, including cirrhosis
✓ Appendicitis, colitis, and other intestinal problems
✓ Eye irritation
✓ Gynecological problems
Studies Support Castor Oil's Efficacy as an Antimicrobial, Anti-Inflammatory, and Immunostimulant
While castor oil has been thoroughly investigated for its industrial use, only a minimal amount of research has been directed toward its medicinal benefits. That said, the healing properties of castor oil appear to have survived countless generations of scrutiny. I believe it has enough history behind it to at least warrant greater scientific exploration, and perhaps a little careful at-home experimentation on your own. Oftentimes, modern day scientific studies end up validating thousands of years of "folklore." Castor oil studies are hard to track down, but I did find a few notable ones, which I have summarized in the table below.
✓ Castor oil has been found to have a strong suppressive effect on some tumors.
✓ An Indian study in 2011 found that castor leaf extract showed better antibacterial activity against both Gram-positive and Gram-negative bacteria than Gentamycin (their standard for comparison).11
✓ A 2010 study found that castor oil packs were an effective means of decreasing constipation in the elderly.12
✓ This 2009 study found that castor oil effectively relieves arthritis symptoms.13
✓ A 1999 study14 was carried out to determine whether or not topical castor oil would stimulate the lymphatic system. The findings were positive. After a two-hour treatment with castor oil packs, there was a significant increase in the number of T-11 cells, which increased over a seven-hour period following treatment.
✓ In this 2000 study15 of the effects of ricinoleic acid on inflammation, researchers found it exerted "capsaicin-like" antiinflammatory properties.
✓ Patients with occupational dermatitis may have a positive reaction to castor oil or ricinoleic acid.16
Castor Oil May Promote Healing by Boosting Your Lymphatic System
One of the more compelling health benefits, if true, is castor oil's support of your immune system. And this healing property does not require you ingest the oil, but only apply it externally.
The benefits of castor oil packs were popularized by the late psychic healer Edgar Cayce, and then later researched by primary care physician William McGarey of Phoenix, Arizona, a follower of Cayce's work and the author of The Oil That Heals. McGarey reported that, when used properly, castor oil packs improve the function of your thymus gland and other components of your immune system. More specifically, he found in two separate studies that patients using abdominal castor oil packs had significant increases in lymphocyte production compared to placebo packs.
Lymphocytes are your immune system's disease-fighting cells and are produced and stored mainly in your lymphatic tissue17 (thymus gland, spleen, and lymph nodes). Hundreds of miles of lymphatic tubules allow waste to be collected from your tissues and transported to your blood for elimination, a process referred to as lymphatic drainage. When your lymphatic system is not working properly, waste and toxins can build up and make you sick.
Lymphatic congestion is a major factor leading to inflammation and disease. This is where castor oil comes in. When castor oil is absorbed through your skin (according to Cayce and McGarey), your lymphocyte count increases. Increased lymphocytes speed up the removal of toxins from your tissues, which promotes healing.
Castor Oil Packs a Punch, Topically
Castor oil "packs" can be an economical and efficient method of infusing the ricinoleic acid and other healing components of castor oil directly into your tissues. You would be wise to do a "patch test" prior to applying a castor oil pack to make sure you aren't allergic to the oil.
There are several ways to use castor oil topically. You can simply rub castor oil onto an affected area of your skin. Or, you can affix a Band-Aide soaked in castor oil if only a very small area needs to be treated. For larger or more systemic applications, it can be used as massage oil, which is reported especially effective when applied along your spinal column, massaged along your lymphatic drainage pathways. But the coup de grace of castor oil therapy is the "castor oil pack." To make a castor oil pack, you will need the following supplies:
- High quality cold-pressed castor oil (see last section of this article)
- A hot water bottle or heating pad
- Plastic wrap, sheet of plastic, or plastic garbage bag
- Two or three one-foot square pieces of wool or cotton flannel, or one piece large enough to cover the entire treatment area when folded in thirds
- One large old bath towel
Below are instructions for making and using a castor oil pack (courtesy of Daniel H. Chong, ND):
- Fold flannel three layers thick so it is still large enough to fit over your entire upper abdomen and liver, or stack the three squares.
- Soak flannel with the oil so that it is completely saturated. The oil should be at room temperature.
- Lie on your back with your feet elevated (using a pillow under your knees and feet works well), placing flannel pack directly onto your abdomen; cover oiled flannel with the sheet of plastic, and place the hot water bottle on top of the plastic.
- Cover everything with the old towel to insulate the heat. Take caution not to get the oil on whatever you are laying on, as it can stain. If necessary, cover that surface with something to protect it.
- Leave pack on for 45 to 60 minutes.
- When finished, remove the oil from your skin by washing with a solution of two tablespoons of baking soda to one quart water, or just soap and water. (Be sure to wash the towel by itself, as the castor oil can make other clothes stink if washed together.)
- You can reuse the pack several times, each time adding more oil as needed to keep the pack saturated. Store the pack in a large zip-lock bag or other plastic container in a convenient location, such as next to your bed. Replace the pack after it begins to change color.
- For maximum effectiveness, apply at least four consecutive days per week for one month. Patients who use the pack daily report the most benefits.
Be Cautious When Purchasing Castor Oil
As with everything else, you must be careful about your source of castor oil. Much of the oil currently sold in stores is derived from castor seeds that have been heavily sprayed with pesticides, solvent-extracted (hexane is commonly used), deodorized, or otherwise chemically processed, which damages beneficial phytonutrients and may even contaminate the oil with toxic agents.
Again, let me emphasize, many of the health benefits of castor oil are more anecdotal than scientific, and side effects have been reported. As with anything new, proceed carefully so that you can minimize any unexpected reactions. I invite your comments about any experiences—positive or negative—related to your use of castor oil. I am always curious about your impressions and experience with natural remedies, and your feedback is welcome, as always.