Brightly colored changes in the color of your tongue may be caused by eating or drinking something that may have stained your tongue, such as soft drinks or candy. The bright colors can be alarming. Stains caused by soft drinks or candy will brush off or wear off.

A buildup of food debris and bacteria on the tongue may make the tongue look thick or furry ("hairy tongue"). Often the problems will go away if the surface of the tongue is brushed with a soft-bristled toothbrush. If your tongue problem is from some local irritation, such as tobacco use, removing the source of the irritation may clear up the tongue problem. Home treatment may be all that is needed.

Other common causes of tongue problems include:

• Deep grooves (fissures) of the tongue. Although deep fissures on the tongue are often normal, food particles can get stuck in the grooves, causing inflammation and tenderness.
• Lack of certain vitamins or minerals in your diet, especially B vitamins.
• Fungal infections (thrush), which produce white patches on the tongue and inside of the mouth.
• Injuries, such as biting, chewing, piercing, or burning the tongue.

Common tongue problems include:

• Redness and swelling (inflammation) of the tongue (glossitis).
• Smooth tongue, a condition in which the normal rough surface (papillae) of the tongue shrinks or disappears, making the tongue look bald or shiny and thin. Without this rough surface, the tongue may be tender and sensitive to spicy foods.
• Other changes in the surface of the tongue. Your tongue may look like it has grown hair (hairy tongue) or white fur (furry tongue), or it may look like a road map (geographic tongue).
• Changes in the color of the tongue. Your tongue may look black or strawberry- or raspberry-colored.

Rare, but serious, causes of tongue problems can include:

• A severe allergic reaction, causing the tongue to swell. This is an emergency and requires prompt medical evaluation.
• Oral cancer, which can cause a sore on the tongue or a lasting feeling of numbness.