Schoolboy Michael Delaney needed emergency surgery after accidentally swallowing the magnetic tongue studs, which are designed to look like a piercing.
The powerful magnets – which look like ball-bearings – ripped through his intestines and acid from the metal also caused serious damage to his bowel. His injuries could result in lifelong problems.
Michael was one of four pupils at St Matthew’s RC High School in Moston admitted to hospital after swallowing the products.
Michael initially attended North Manchester General Hospital complaining of a stomach upset two weeks after swallowing the tiny metal balls on a bus journey.
Surgeons had to cut into his bowel in three places to retrieve the accessories and later told him he had been just four hours away from losing his life.
After discovering what had caused the horrific internal damage, the school urged any other pupils who had swallowed the ball bearings to go straight to hospital – and circulated a warning letter to parents and other schools.
Three girls from St Matthew’s aged between 13 and 16 were also admitted to hospital as a precaution but were given the all-clear by doctors.