chrisb1
Hello swimmergirl1112,
While the term ‘black tongue’ suggests the tongue surface looks black, it may also be dark yellow, brown, green or white. The tongue papillae are constantly renewing themselves and, usually, the old cells are shed as the new cells emerge. Black tongue, a comparatively rare condition, is caused by the failure of the old cells to shed. The overgrowth of papillae traps food and bacteria, which create the characteristic dark ‘coat’ on the tongue’s surface, while the tongue looks furred because of the layering of unshed papillae.
The cause isn’t known, but risk factors include:
Poor oral hygiene
Cigarette smoking
Particular
Antibiotics
Chemotherapy and radiation treatment for cancers of the head and neck
Poorly managed diabetes.
Metallic Taste...........
http://www.wrongdiagnosis.com/symptoms/metallic_taste/causes.htm
Chrisb1.