Her skin also turned grey (Picture: BMJ)

A woman in her 60s was shocked, to say the least, when her tongue turned black and hairy after she suffered a bizarre reaction to antibiotics.

The patient, in her 60s, had been popping minocycline, used to treat everything from acne to pneumonia, to ease the side-effect of her chemotherapy.

She had been living with rectal cancer and started treatment 14 months ago in Japan, according to the British Medical Journal Case Reports.

Kazuhide Takata and Fumihito Hirai, of the Fukuoka University Faculty of Medicine, said the patient came in for the first time in months for hepatitis B treatment.

But doctors found that the woman’s face had turned grey.

They were stunned once more when the patient opened her mouth revealing a ‘painful’ carpet of black and brown ‘hair-like’ tastebuds.

The woman, who was not named, had been taking drugs to help with the skin lesions caused by chemotherapy (Picture: BMJ)

This is the hallmark symptom of the rather obviously named ‘black hair tongue’ (BHT), a harmless condition caused by not exactly great oral hygiene.

It can always be tricky working out what caused BHT, but changes in the normal bacteria or yeast content in the mouth due to antibiotics are one of them.

Medics ‘strongly’ thought the patient’s fuzzy tongue was down to her taking minocycline, one of a handful of antibiotics that BHT can be a side-effect of.

The grey patches on her face, the doctors said, were ‘characteristic of minocycline-induced skin damage’.

‘Minocycline turns black when oxidised and can lead to skin discolouration,’ they added.

So they switched her onto a different drug regimen instead.

Her BHT thankfully cleared up in only a few weeks, doctors said (Picture: BMJ)

‘Six weeks later, her facial pigmentation and BHT markedly improved.’ the doctors said, though they did not specify when this took place.

‘In this case, the disease course suggested that it was an adverse reaction to minocycline.’

The condition sees the countless bumps covering the tongue, called papillae, turn black and, due to the build-up of dead skin cells, stick out like hair.

Bacteria can also get tangled up in the tongue, as does yeast, tobacco, food and all sorts of other smelly substances, giving the tongue a woolly appearance.

Bad breath is, unsurprisingly, a symptom of BFT.

People may also feel they can always taste metal and, if the tongue is especially furry, feel like they need to gag.

But BHT, as alarming as it looks, isn’t anything to get spooked by.

It’s usually the symptom of a rather easy-to-fix problem, such as a liquid diet (solid foods scrape the tongue of dead skin cells) or smoking.

Over time, the tongue will get a haircut and the black colouration will fade away as people are advised to brush their tongue to remove the dead skin cells and drink plenty of water.

But if the condition proves too stubborn and a patient’s tongue likes their toupee, a doctor can remove them using a carbon dioxide laser.

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Her face also turned completely grey.