Three young girls from Nottinghamshire have been admitted to hospital after swallowing small magnetic parts designed to look like fake tongue piercings.
The girls, all in their early teens, suffered with abdominal complications.
Two of them required major bowel surgery to remove the magnetic parts.
Public Health England alerted trading standards teams at both Nottingham City and Nottinghamshire County councils, which are now warning young people and their parents not to buy or use the parts.
Both councils have also sent out letters to schools and headteachers to highlight the dangers of this new craze among children.
Councillor Toby Neal, portfolio holder for community protection at Nottingham City Council, said: "It is really concerning that this is happening and we hope that these young girls recover quickly.
"Children are using these high powered magnets to mimic having a tongue piercing and they are not thinking about the dangers, which in some cases can be life-threatening.
"We would ask parents and guardians to warn young people about the dangers of placing these products in their mouths and to seek urgent medical attention should these products be swallowed.
"These products are legal and our trading standards team cannot remove them from sale.
"However, we feel they are dangerous and should be outlawed."
Coun Gordon Wheeler, vice-chairman of the communities and place committee at the city council, added: "Our thoughts are with the three girls hurt by these products and we wish them a speedy recovery from their ordeal.
"It's vitally important that children and parents are made aware of the potentially deadly health risks that wearing these fake tongue piercings can pose.
"As the products have a legal status, our trading standards teams are powerless to act against any shops or websites that have them for sale.
"However, we are appealing to all responsible retailers to withdraw them from sale immediately and we are calling on MPs and the Government to ban these products at the earliest opportunity."