A TikTok trend where teenagers use tiny magnets as fake tongue piercings has prompted the NHS to call for the metal balls to be banned.
The viral challenge involves people putting two magnetic balls on either side of their tongue to give the appearance of a tongue piercing.
But accidentally swallowing more than one magnet can be life-threatening and cause serious damage within hours.
The NHS said there has been a rise in hospital admissions among older children as many have taken part in the online craze, leading the NHS to issue a patient safety alert earlier this month.
An 11-year-old is among those who suffered serious complications after apparently swallowing several of the magnets, according to Worcester News.
Ellis Tripp was rushed to hospital and forced to undergo a six-hour operation to remove five inches of his bowel.
His mother, Amy Clarke, pleaded with other parents to watch out for the TikTok trend.
"I'm in a nightmare. This TikTok craze could/would have killed him if left any longer. Please talk to your children and tell them how DANGEROUS THESE ARE," she wrote on Facebook.
A 13-year-old girl is also reported to have had major surgery after trying out the social media trend.
Her mother, Faye Elizabeth from Rainhill, said her daughter swallowed 15 of the magnetic beads, according to the Liverpool Echo.
The tiny balls are less than 6mm in diameter and can be easily swallowed.
Once ingested, they can become forced together in the intestines or bowels, squeezing the tissue and cutting off the blood supply.
At least 65 children have been admitted to hospital in England for urgent surgery after swallowing magnets in the last three years.
Professor Simon Kenny, paediatric surgeon and national clinical director for children and young people at NHS England, has called for the magnets to be banned.
He said: "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, or the long-term physical problems and internal scarring that can be left behind.
"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."
The NHS said anyone who has swallowed magnets should not wait to develop symptoms and should instead go to A&E immediately.