Castor Oil Taken Internally

Probably the most common use of castor oil historically and around the world is as a powerful laxative. Grandmothers knew it and the FDA even agrees, having approved it as an over-the-counter stimulant laxative. Ricinoleic acid is responsible for the laxative effects, as it stimulates the muscles of the intestines causing contractions that promote bowel movements.³ While stimulant laxatives like castor oil can be effective for relief of occasional constipation, they should not be relied on regularly as they can cause dependency.

Castor Oil Types

Plain yellow castor oil is usually made simply by cold-pressing castor beans. Black Castor Oil is made by roasting the castor beans first, a processing method said to have been developed in Jamaica. The ash from roasting is what gives black castor oil its color and is believed to increase the pH of the castor oil. Both contain high amounts of ricinoleic acid, and their benefits are likely similar, although black castor oil is less commonly used internally.

Castor Oil Applied Externally

Castor oil is often recommended for hair, skin, and nail health and can be found in many beauty products. It is highly emollient and suitable for softening rough dry skin and, because it is viscous, it provides staying power and shine (making it a good ingredient for lipsticks and lip gloss) and may help protect nails from drying conditions.⁴ Although castor oil is credited with a wide range of benefits for hair, skin, and nail conditions, nearly all evidence is anecdotal. There is some evidence that regular application may modulate inflammation and help with minor pains in a manner similar to that of capsaicin (extracted from chili peppers) but without the burn.^{5 6} In a computer model, ricinoleic acid was predicted to inhibit prostaglandin D2 synthase, a possible target for treating hair loss.⁷ However, a review of 22 studies comparing the benefits of coconut oil, castor oil, and argan oil for hair found castor oil to have limited support for improving luster, but no strong evidence that it promoted hair growth (or was able to treat infestation).⁸

Castor Oil Packs

Castor oil packs were popularized in the US by Edgar Cayce, a healer and clairvoyant practicing in the early 1900s. They are still often recognized in natural medicine, but how and if they work remains a mystery, since we don’t know definitively whether topically applied castor oil is absorbed into the body.⁹ Castor oil packs are commonly recommended for aching limbs, constipation, menstrual cramps, migraines, to break up adhesions, and for liver and gallbladder health. One small study found higher lymphocytes (specifically T-11 cells) in healthy participants after doing a castor oil pack treatment versus the control, suggesting castor oil may support immune function.¹⁰ Another study found that castor oil pack treatment in constipated elderly patients for 60 minutes a day, three days a week, did not increase the number of bowel movements or the amount of feces passed, but did improve symptoms of constipation, such as fecal consistency, straining, and feeling of complete evacuation after a bowel movement.¹¹

How to do a castor oil pack. Prepare your space. Lay an old towel down where you will be and, optionally, cover it with a plastic sheet or large trash bag. If you wish to use a heating pad or hot water bottle, get it ready too. (Heat is generally recommended except in cases of active infections, bleeding, excessive gas, or injury less than 48 hours old.¹²) Saturate a wool or cotton flannel piece of cloth with castor oil and place it on the body. The location is determined by the desired outcome. For general use, place the pack over the mid-section of the body from the sternum to about 4 inches below the navel and to the right to cover the liver. Cover the pack with plastic (a trash bag or plastic wrap works well), then place the heating pad/hot water bottle over the pack. Lie back and relax for at least 1 hour and up to 2. When finished, take the pack off and wrap it in the plastic wrap you used to cover the pack (or store in a zip top bag or glass jar) for later use. If you wish, clean the castor oil off your body with warm water and soap or a small amount of baking soda. Aim for three consecutive days of castor oil pack sessions per week to begin and then taper to one day a week for maintenance. Beware, castor oil packs can be very messy and castor oil does stain, so protect your furniture and clothing.

Castor Oil Safety

Castor oil is well recognized as safe for external use, although it could trigger an allergy, such as a skin rash, in a small percentage of the population, so it is best to spot test if you have sensitive skin. Caution should be exercised when using castor oil around the eyes to avoid eye irritation.¹³ Taken internally, castor oil can cause cramping, diarrhea, and loss of electrolytes, especially if taken in high doses or used long term. If you are pregnant, castor oil should only be used under the guidance of a trained midwife or doctor. Finally, although the castor bean does contain a highly poisonous compound called ricin, the oil is completely free of it.

References

1. n.a. Castor. American Botanical Council website. Retrieved from https://www.herbalgram.org/resources/healthy-ingredients/castor/
2. Fitranda, M.I., Sutrisno, Marfu’ah, S. (2020). Physiochemical properties and antibacterial activity of castor oil and its derivatives. IOP Conf. Ser: Mater Sci Eng. 833, 012009. DOI 10.1088/1757-899X/833/1/012009
3. Alookaran, J., Tripp, J. (2022). Castor Oil. StatPearls Publishing. Retrieved from: https://www.ncbi.nlm.nih.gov/books/NBK551626/   
4. Tourles, S. (2007). Organic Body Care Recipes: 175 Homemade Herbal Formulas for Glowing Skin & a Vibrant Self. Storey Publishing.
5. Vieira, C., Evangelista, S., Cirillo, R., Lippi, A., Maggi, C.A., Manzini, S. (2000). Effect of ricinoleic acid in acute and subchronic experimental models of inflammation. Mediators Inflamm, 9(5), 223-228. doi: 10.1080/09629350020025737
6. Vieira, C., Evangelista, S., Cirillo, R., Terracciano, R., Lippi, A., Maggi, C. A., & Manzini, S. (2000). Antinociceptive activity of ricinoleic acid, a capsaicin-like compound devoid of pungent properties. European journal of pharmacology, 407(1-2), 109–116. https://doi.org/10.1016/s0014-2999(00)00727-5
7. Fong, P., Tong, H.H.Y., Ng, K.H., Lao, C.K., Chong, C.I., Chao, C.M. (2015). In silico prediction of prostaglandin D2 synthase inhibitors from herbal constituents for the treatment of hair loss. J Ethnopharmacol, 175, 470-480. https://doi.org/10.1016/j.jep.2015.10.005
8. Phong, C., Lee, V., Yale, K., Sung, C., Mesinkovska, N. (2022). Coconut, castor, and argan oil for hair in skin of color patients: a systematic review. J Drugs Dermatol, 212(7), 751-757. DOI: 10.36849/JDD.6972
9. Mein, E.A., Richards, D.G., McMillin, D.L., Nelson, C.D. (2005). Transdermal absorption of castor oil. Evid Based Integrative Med, 2(4), 239-244. Retrieved from: https://www.meridianinstitute.com/reports/transdermal.pdf
10. Grady, H. (n.d.). Immunomodulation through castor oil packs. J Naturopathic Med, 7(1), 84-89. Retrieved from: https://drprincetta.com/wp-content/uploads/2016/01/Castor-Oil-Packs-Immunomodulation.pdf
11. Arslan, G. G., & Eşer, I. (2011). An examination of the effect of castor oil packs on constipation in the elderly. Complementary therapies in clinical practice, 17(1), 58–62. https://doi.org/10.1016/j.ctcp.2010.04.004
12. Therapies: Castor oil packs. Therapies: Castor Oil Packs | Edgar Cayce’s A.R.E. (n.d.). https://www.edgarcayce.org/the-readings/health-and-wellness/holistic-health-database/therapies-castor-oil-packs/
13. Maduri, V.R., Vedachalam, A., Kiruthika, S. (2017). ”Castor oil” – the culprit of acute hair felting. Int J Trichology, 9(3), 116-118.  doi: 10.4103/ijt.ijt_22_17