Certain diseases and medicines can affect how much saliva you make. If you do not make enough saliva, your mouth can become quite dry. This condition is called dry mouth (xerostomia).
Dry mouth causes the gums, tongue, and other tissues in the mouth to become swollen and uncomfortable. Germs thrive in this type of setting. A germy, dry mouth leads to bad breath.
Dry mouth also makes you more likely to develop rapid tooth decay and gum (periodontal) disease. That's because saliva helps clear food particles from your teeth. This helps reduce your risk for cavities.
If you have dry mouth, you may also notice you do not taste things like you used to.