healthHealth and Medicine

"Black Hairy Tongue" – What Is It, Exactly?


Robin Andrews

Science & Policy Writer

Ick. BravissimoS/Shutterstock

Black Hairy Tongue (BHT) sounds, and looks, like an apocalypse petit dejeuner for one – but it’s not. It looks totally bizarre, though, which is why a recent report in the New England Journal of Medicine has got everyone’s attention. So what the heck is it?

The Mayo Clinic describes it as a “temporary, harmless oral condition”, one that turns the tongue’s surface dark and furry. It may look like you’ve been possessed, strangely via the tongue, but it’s merely an accumulation of dead skin cells on the papillae structures, the tiny towers containing taste receptors.


You may have noticed that drinking dyed foods can turn your tongue the very same hue. That’s because the papillae are excellent at retaining chemical compounds, like those found on things like tobacco and food and so on. For the same reason, BHT – which is just dead cells, really – shows up more because it’s not as easy to dislodge the cells as you may think.

BHT, “thought unattractive”, is normally painless, and it usually disappears once the root has been treated. Such antagonizing factors include, but aren’t limited to, poor oral hygiene, the use of mouthwashes that contain things like peroxide, excessive alcohol consumption, tobacco use, eating too much smushy food that can’t literally clean your tongue, dry mouth, and drinking too much coffee or black tea.

The New England Journal of Medicine (c) 2018

This latest case was a little different, however. The patient, a 55-year-old woman, was injured in a traffic collision. The wounds on her crushed legs became infected, so she was given minocycline, a general antibiotic. Within a week, she had BHT.

Clearly, it was related to the minocycline, but this rare side effect can’t be explained at present. Having been given a different antibiotic, and “advised to practice good oral hygiene,” the woman's condition disappeared within four weeks.


Importantly, you don’t have to worry about taking antibiotics in this sense. BHT is super rare, even if it crops up in medical journals, such as BMJ Case Reports, from time to time.

If you do get it, it won’t be permanent. Far better to fret over antibiotic resistance instead, methinks, which is currently engaging in a bit of a world tour.


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