Castor oil, which was once used by fascists in Italy as punishment because of its quick-acting laxative effect, is now a weight-loss trend on TikTok. Not drinking it, but rubbing it on your belly.

Influencers are also pouring it in their belly buttons and wrapping towels soaked in it around their midriff. They claim it can melt belly fat and help with bloating.

Castor oil – made from the beans of the castor plant – is an ancient medicine. References to it appear in an ancient Egyptian medical text called the Ebers Papyrus (1550BC). It was used as a laxative and to treat various skin conditions. Cleopatra is said to have used it in her hair and to brighten the whites of her eyes.

The odourless oil is rich in a fatty substance called ricinoleic acid that strongly stimulates bowel movements. Today, it is an approved over-the-counter remedy in some countries for short-term constipation and is used for cleansing the bowel before medical examinations. However, there’s not much scientific evidence to indicate that this laxative effect is better than other commonly used laxatives, such as senna – which has also been used for centuries.

Other reported traditional uses for the oil include as a cure for sore and itchy eyes, to relieve joint and period pain, and as a means to induce labour. But, again, the evidence for these things is scant.

Castor oil isn’t just imbibed, it is also widely used in skin creams, hair conditioners and other cosmetic products, such as lipsticks. It is used to moisturise, soothe irritated skin and reduce the appearance of wrinkles. Its moisturising properties have been attributed to ricinoleic acid.

As part of haircare products, it is said to help with hair loss and dandruff.

But taking castor oil as a standalone product is not risk free. The main side-effects of imbibing the oil are abdominal cramps, vomiting, bloating and dizziness.

Vulnerable people, such as the elderly, babies, pregnant or breastfeeding women, and those with liver or kidney failure should avoid taking castor oil. As should anyone with inflammatory bowel disease, appendicitis or gastrointestinal obstruction or perforation.

The side-effects of castor oil can also be exacerbated in people with eating disorders who may choose to use the oil to lose weight by speeding up the passage of food through the gut.

However, if you want to apply the oil to your skin or scalp, proceed with caution. In some people, it can trigger an allergic reaction.

It is always advised to apply a small amount of pure castor oil or a castor oil-containing cosmetic product onto a small patch of skin. If there is no allergic reaction after 24 hours, then it can be assumed that the product can be applied safely to a larger area of the body.

Ultimately, though, there are generally safer and better remedies out there. And rubbing it on your belly – sadly – won’t melt the fat.