Black hairy tongue sounds like something from a medical horror story, yet it has more in common with a stained shag rug than with an illness. Tiny projections on the top of the tongue grow longer than usual, trap pigment, and look dark and furry. It is harmless, it is not hair, and in most people it fades within a few weeks once the cause is dealt with and the tongue is cleaned each day.
Long papillae act like a pile that catches stain
The top of the tongue is covered in thousands of small, cone-shaped projections called filiform papillae. They normally wear down and shed as you eat, talk and swallow. When shedding slows, they keep growing and form a thick layer, much like an unmown lawn. Food pigments, tobacco tar and colour-producing bacteria and yeasts collect in that layer, which is where the colour comes from.
The colour is often black or dark brown, but it can be green, yellow or tan. It usually sits on the middle and back of the top of the tongue and spares the tip and sides. Most people notice nothing except the look. Others mention a tickling or gagging feeling, a metallic or odd taste, or bad breath.
Published reviews put its prevalence anywhere from under 1 percent to around 11 percent depending on the population studied. It is seen more often in older adults, in men, and in people who smoke.
The usual reasons shedding slows down
Several factors tend to combine:
- Tobacco. Smoking and chewing tobacco both stain the papillae and are among the most frequent associations.
- Dark drinks. Large amounts of coffee or black tea add pigment.
- A soft diet. Rough, raw foods may help scrub the tongue surface, so a mostly soft or liquid diet, for example after surgery or during illness, may let papillae build up.
- Dry mouth. Saliva helps clear the tongue. Medicines, dehydration and some medical conditions reduce it, which our article on dry mouth explains.
- Antibiotics and some other medicines. Several antibiotics have been linked with it, possibly by upsetting the normal mix of bacteria and yeasts in the mouth. Some antipsychotics and other drugs that dry the mouth have also been linked.
- Certain mouth rinses. Prolonged use of oxidising rinses, such as those containing peroxide, has been reported as a contributor.
- Not cleaning the tongue. Brushing the teeth but never the tongue lets the layer thicken.
Not every dark tongue is black hairy tongue
A tongue can turn dark for other reasons, and the difference matters. Bismuth, found in some stomach-settling medicines, can turn the tongue and stools black; this is a surface stain that fades after stopping the product, not overgrown papillae. Strongly coloured foods, drinks and lollies can stain the tongue for a few hours too.
A white coating that wipes off and leaves a red, sore surface may be oral thrush. A white, ridged patch on the sides of the tongue that cannot be wiped away is a different condition again and should be examined. Any dark spot or patch that is flat, raised or growing, rather than a furry coating over the whole surface, needs a dentist or doctor to look at it.
Clearing it at home usually works
Treatment starts with the likely trigger. Cutting down or stopping smoking, easing back on coffee and tea, drinking more water, and replacing a peroxide rinse with plain water often makes a noticeable difference. If an antibiotic seems to be the cause, finish the course as prescribed; the change usually settles afterwards. Do not stop a prescribed medicine without talking to your doctor.
Then clean the tongue once or twice a day. Use a soft toothbrush or a tongue scraper, start as far back as you comfortably can, and draw it forward with gentle, even strokes, rinsing as you go. Scrubbing hard is unnecessary and can make the tongue sore. Our guide to tongue scraping shows the technique, and good daily brushing, covered in our article on brushing your teeth properly, supports the result.
Many people see improvement within days to a few weeks. Long-standing cases linked to smoking or ongoing dry mouth can take longer, and the coating may return if the trigger comes back.
Breath often improves at the same time
The deep layer on the tongue also holds bacteria that release sulphur compounds, so black hairy tongue and bad breath often go together. Cleaning the tongue usually helps both. If breath odour hangs on after the tongue looks normal, other sources such as gum disease or tonsil stones are worth checking, which our article on bad breath covers.
Signs it needs a professional look
Book in with a dentist or OHT if the coating has not improved after about two weeks of daily cleaning and removing likely triggers, if your tongue burns or hurts, or if there is a patch, lump or ulcer that does not brush away. Any change in the mouth that has not settled within three weeks should be examined. In some stubborn cases a dentist may trim the papillae or suggest other treatment, but that is uncommon.
If you would like your tongue checked, you can book with a general dentist in Melrose Park and see any current offers on our deals page.
