You might already know this, but if your tongue ever starts turning black and growing hair, you should go see a doctor right away. Keep your freak-out under control, though, because it's probably a temporary condition.
A 55-year-old Missouri woman woke up one morning in 2017 feeling nauseated with a bad taste in her mouth. Upon looking in the mirror, she decided to get a doctor involved: It appeared that her tongue had begun to sprout dark hairs.
The woman, it turned out, had developed a condition known as "black hairy tongue" — BHT, or lingua villosa nigra — and you can imagine her relief when she discovered it isn't permanent or particularly dangerous, just kind of gross. But black hairy tongue is a sign that not all is right within.
According to a study published Sept. 6, 2018, in the The New England Journal of Medicine, the woman had been taking an antibiotic called minocycline during treatment for a wound infection that resulted from both her legs being crushed in a car accident. About a week into her course of antibiotics, her filiform papillae — the little bumps on the tongue that give it texture and sensation — started growing long and discolored. The antibiotic had caused the papillae to trap bacteria, stretch out and turn black. Her doctor took her off the medicine and told her to be extra vigilant in her oral hygiene regimen. Within a month, her tongue was back to normal.
Black hairy tongue is uncommon, but often associated with poor oral hygiene, heavy tobacco use or a diet that contains a lot of coffee or alcohol. It's not dangerous, but it's a good cautionary tale: Let's all keep an eye on our tongues!