Health expert and broadcaster Dr Xand van Tulleken has explained the danger of the tongue-scraping trend which gets millions of views for videos on social media. The trend sees people buying a specialist tool to scrape their tongues every day - which is supposed to improve oral health and get rid of bad breath.

Speaking on the BBC series Con or Cure, Dr Xand watched one of the videos that showed a woman demonstrating how to scrape your tongue with a tool. He said: "Your tongue is designed to be constantly worn away by food and by running over your teeth cleaning up your mouth. And when that doesn't happen it grows a thick layer of fur that actually turns almost a sort of yellowy-brown.

"Now bacteria can live in that fur." Talking about hospital patients who are nil-by-mouth before or after surgery, Dr Xand said: "Often their breath was very bad."

He added: "Oral hygiene including abrading your tongue with either a tongue scraper or a toothbrush is kind of an important part of cleaning your tongue and keeping your mouth in good shape."

He added: "I brush my tongue and give it a good scrub. The tongue scraper is doing a very similar thing." But Dr Xand explained: "Let me just give you one caveat. If you are struggling with severe halitosis - if you have bad breath - that is not necessarily coming from your tongue.

"It could be coming from gum disease and gum disease is a big deal. That can shorten your life, it can cause all kinds of problems and you may have other problems in your mouth as well - or problems with your digestion."

He concluded: "Social media is not a great place to get health advice, not because there's anything really wrong with tongue scraping - but it may not be treating your problem.

"If you go to your dentist or your oral hygienist they may say 'there's nothing wrong with your tongue, you've got gum disease and you need to be sorted out for that instead."

Dr Xand says there is no point buying a tongue scraper as you can clean your tongue with a spoon or toothbrush and if you have a problem you should see your dentist