It dates back hundreds of years and has gained popularity with today's youth but dentists said today tongue-piercing can have serious complications.
Apart from infection, bleeding and scarring, it can also cause cracked teeth and nerve damage.
"Piercing of oral sites may lead to a number of complications, some of which are life-threatening," said Mr Tamer Theodossy, of University College London.
In a report in the British Dental Journal, Theodossy described how the tongue of a woman (28) swelled and totally encased a barbell pierced through it. The woman needed surgery to remove it.
"Piercing of oral sites also carries a high risk of infection with the possibility of transmission of organisms such as HIV, hepatitis B and C, Herpes Simplex virus, Epstein-Barr virus and candida," he added.
Herpes Simplex is linked to cold sores, and the Epstein-Barr virus causes glandular fever.
Dr Mervyn Druian, of the British Dental Association, also advised against tongue piercing because of the potential complications. "The trouble is, it has became a fashion accessory for some people," he said.