Castor Oil: Uses, History and What the Research Says (2026 Guide)
Many Australians remember castor oil as the spoonful of something awful their grandparents swore by. Now it’s trending again, with castor oil packs, “hair growth” routines and lash serums all over social media. So what’s real and what’s hype? This guide looks at where castor oil comes from, how it works, and what the research actually shows.
Where does castor oil come from?
Castor oil is pressed from the seeds (“beans”) of Ricinus communis, a fast-growing plant native to north-east Africa that’s now found worldwide. In parts of Australia it grows wild as a weed along creeks and roadsides.
The raw seeds contain ricin, a highly toxic protein. Ricin doesn’t dissolve into the oil, and commercial processing (including heating) removes and destroys any traces. The seeds themselves should never be eaten, and children and pets should be kept away from the plant.
Castor oil has been used for thousands of years. The ancient Egyptians burned it in lamps and used it in skin preparations. Today it’s also a major industrial oil, used in lubricants, paints and cosmetics.
What makes it different?
About 90% of the fat in castor oil is ricinoleic acid, an unusual fatty acid found in very few other oils. It gives castor oil its thick, sticky texture.
In 2012, researchers in Germany worked out how castor oil acts as a laxative. Ricinoleic acid activates a specific receptor (the prostaglandin EP3 receptor) on smooth muscle cells in the gut and the uterus. That explains both its laxative effect and its traditional use to bring on labour (Tunaru et al., 2012).
Constipation
Castor oil taken by mouth is a powerful stimulant laxative, and it works, usually within a few hours. But it can cause strong cramping, and frequent use can lead to dehydration and loss of electrolytes. Today, gentler options are generally recommended first (Alookaran and Tripp, StatPearls).
Castor oil packs
A castor oil pack is a cloth soaked in castor oil, placed on the skin (usually the abdomen), often with gentle warmth. A small Turkish study of older adults with constipation found castor oil packs on the abdomen eased some symptoms, such as straining, but didn’t change how often people opened their bowels (Arslan et al., 2011). It was a small study without a placebo group.
Online claims that castor oil packs “detox the liver”, shrink cysts or balance hormones aren’t supported by clinical research. Put plainly: for most claims about castor oil packs, the evidence simply doesn’t exist yet.
Hair and lashes
Castor oil is hugely popular for hair, brows and lashes. As a thick oil, it can coat the hair shaft, reduce breakage and make hair look shinier. But there’s little evidence that it makes hair grow. A 2022 systematic review of coconut, castor and argan oil for hair found no high-quality clinical trials showing castor oil promotes hair growth (Phong et al., 2022).
Castor oil and labour: not a DIY option
Castor oil has a long folk history for “bringing on” labour. A Cochrane review found too few good-quality trials to draw firm conclusions, and noted that all women who took castor oil by mouth felt nauseous (Kelly et al., 2013). A 2022 meta-analysis found possible effects on cervical ripening but also stressed the need for more research (Moradi et al., 2022). Never use castor oil in pregnancy unless your midwife or obstetrician specifically advises it.
On the skin
Castor oil is a common ingredient in lip balms, soaps and creams, where it acts as an emollient (it softens and helps hold moisture in the skin). Because it’s so thick, many people dilute it with a lighter oil such as jojoba or sweet almond oil. Its ricinoleic acid can occasionally cause allergic contact dermatitis.
Who should take care?
We’re not aware of a current TGA safety advisory specific to castor oil. However:
- Pregnancy: do not take castor oil by mouth during pregnancy unless directed by your maternity care team, as it can trigger contractions.
- Children: don’t give castor oil as a laxative to children without medical advice.
- Bowel conditions: avoid oral use if you have abdominal pain of unknown cause, bowel obstruction, appendicitis or inflammatory bowel disease.
- Frequent laxative use: can cause dehydration and low potassium, which matters if you take diuretics or heart medicines.
- Skin and eyes: patch test before using on skin, and take care near the eyes. Stop if you get redness or irritation.
- Raw seeds: never eat castor beans. They are poisonous.
The bottom line
Castor oil has a long history and a clear laxative effect, now explained by modern research. Beyond that, the evidence is thin: small studies on castor oil packs, no good trials showing it grows hair, and safety concerns about using it to induce labour. It’s a useful emollient and a traditional remedy, but don’t believe every trending claim.
This article is general information only and is not medical advice. It is not about any specific product. Talk to your GP or pharmacist about your own health. Safety information is current as at 24 October 2026; always check the TGA website for the latest advice.
References
- Tunaru S, et al. Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors. Proc Natl Acad Sci U S A. 2012. https://pubmed.ncbi.nlm.nih.gov/22615395/
- Alookaran J, Tripp J. Castor oil. In: StatPearls. Treasure Island (FL): StatPearls Publishing; updated 2024. https://pubmed.ncbi.nlm.nih.gov/31869090/
- Arslan GG, Eşer I. An examination of the effect of castor oil packs on constipation in the elderly. Complement Ther Clin Pract. 2011. https://pubmed.ncbi.nlm.nih.gov/21168117/
- Phong C, et al. Coconut, castor, and argan oil for hair in skin of color patients: a systematic review. J Drugs Dermatol. 2022. https://pubmed.ncbi.nlm.nih.gov/35816075/
- Kelly AJ, et al. Castor oil, bath and/or enema for cervical priming and induction of labour. Cochrane Database Syst Rev. 2013. https://pubmed.ncbi.nlm.nih.gov/23881775/
- Moradi M, et al. Effect of castor oil on cervical ripening and labor induction: a systematic review and meta-analysis. J Pharmacopuncture. 2022. https://pubmed.ncbi.nlm.nih.gov/35837141/
