In England, 65 children have needed urgent surgery after swallowing magnets in the last three years.
An online trend that involves using tiny magnets as fake tongue piercings has led the NHS to call for them to be banned amid people swallowing them.
Ingesting more than one of them can be life-threatening and cause significant damage within hours.
In England, 65 children have required urgent surgery after swallowing magnets in the last three years.
The NHS issued a patient safety alert earlier this month and is now calling for the small metal balls to be banned.
It said the “neodymium or ‘super strong’ rare-earth magnets are sold as toys, decorative items and fake piercings, and are becoming increasingly popular”.
It added that unlike traditional ones, “these ‘super strong’ magnets are small in volume but powerful in magnetism and easily swallowed”.
The online trend sees people placing two such magnets on either side of their tongue to create the illusion that the supposed piercing is real.
But when accidentally swallowed, the small magnetic ball bearings are forced together in the intestines or bowels, squeezing the tissue so that the blood supply is cut off.
Prof Simon Kenny, paediatric surgeon and national clinical director for children and young people at NHS England, said accidental swallowing of them can cause “long-term physical problems and internal scarring”.
“There is nothing fun for children or their parents about surgery to remove magnets that have been swallowed and become stuck together through different parts of the intestines,” he said.
“I would urge parents to be aware of the dangers associated with magnetic toys but ultimately, the only way we can prevent future incidents is to stop these items being sold altogether.”
According to the NHS, there has been a rise in hospital admissions among older children as teenagers create videos using the magnets on social media.
Unlike traditional magnets, the ones used for such tricks are less than 6mm in diameter and can be easily swallowed.
Natasha Crookes, of the British Toy and Hobby Association, said: “The BTHA believes the law should change to classify these types of products as toys so they have to meet strict toy safety regulations.
“That would mean a change in design to ensure the magnets are covered by a casing too large to swallow.”
The NHS cited the case of 18-month-old twins who both recently ingested magnets that had been bought as toys for their older siblings.
A scan revealed one of the twins had swallowed 23 of them which closed into a loop in his intestines and required emergency surgery at Addenbrooke’s Hospital, Cambridge.
The other child had swallowed four and needed keyhole surgery to remove them.
Both boys have since recovered.
The NHS has urged people not to wait for symptoms if magnets are swallowed and said they should seek help at A&E immediately.