
Black tongue involves a discoloration of the tongue which usually turns it to a blackened color, frequently accompanied by a hairy or fuzzy appearance. A change in the color, size, appearance, or function of the tongue can often be more alarming than it is harmful. Most instances of a black tongue are temporary and not harmful, and the treatment will often simply involve avoiding further use of the reactant.
Black tongue can be a startling sight, but it is usually indicative of a minor or temporary issue. Patience is often the only necessary treatment for black tongue. Changes in the appearance of the tongue may include abnormalities of color or texture. The appearance of a black tongue may also include a hairy look in a condition aptly named black hairy tongue.
A black tongue is most frequently the result of a lack of oral hygiene. Not brushing or flossing regularly, combined with an unhealthy diet can cause black tongue. Frequently drinking coffee or tea, two substances which are notorious for staining teeth, can also cause black tongue. As such, brushing teeth at least twice a day, flossing once, and brushing the tongue each day are the main treatments for black tongue.

Not getting enough fluids can also lead to black tongue. According to WebMD, dehydration is often a cause of black tongue. In this case, the treatment for black tongue is as simple as drinking the recommended daily amount of water; this is generally in the range of eight cups of water per day, depending on a person’s size, living climate, and activity level.
Use of cigarettes or chewing tobacco can cause a blackening of the tongue with a fuzzy or otherwise strange texture, per the National Institutes of Health. This may persist on and off until the use of tobacco is discontinued.
According to the Mayo Clinic, black tongue can also be the result of a reaction to certain medications, including Pepto-Bismol, frequently because of the presence of the chemical bismuth. WebMD also reports that certain mouthwashes, particularly those containing peroxide or menthol, can cause black tongue; when this is the case, switch to an alternative mouthwash.
If black tongue does not disappear after improving oral hygiene practices or eliminating the suspected cause, talk to your doctor. Black tongue may be brought on by a reaction to an antibiotic or after receiving radiation. Black tongue itself is usually not harmful, but if the condition persists, it may be indicative of a medical problem.