Causes of white tongue include, for example:

1. Not cleaning the inside of your mouth properly.
2. Dehydration — when the body doesn't have enough water and other fluids to work as it should.
3. Alcohol use
4. Smoking or using other tobacco products by mouth.
5. Mouth breathing.
6. Low fiber diet — eating mostly soft or mashed foods.
7. Irritation from sharp tooth edges or dental appliances.
8. Fever

Examples of conditions related to white patches or other conditions that can change the color of your tongue include:

1. Use of certain medicines, such as using antibiotics for a long time. This may bring on an oral yeast infection.
2. Oral thrush
3. Geographic tongue
4. Leukoplakia
5. Oral lichen planus
6. Mouth cancer
7. Tongue cancer
8. Syphilis
9. Low immunity caused by diseases such as HIV/AIDS.