When you produce a normal amount of saliva, you rarely give it a second thought. But when you produce little or no saliva, you develop xerostomia, or dry mouth. This condition can make it difficult to swallow and to taste foods, plus it harms your digestion by removing an important enzyme found in saliva. Xerostomia also may lead to tooth decay because saliva helps prevent bacteria in your mouth.
Medications
Many medications -- usually prescription ones -- can cause dry mouth. The Mayo Clinic reports that these range from antidepressants to decongestants and antihistamines. Many older people suffer from dry mouth, and doctors used to think the aging process caused the condition. But the elderly often take many medications for conditions such as high blood pressure, and physicians now think those drugs, rather than aging itself, are what cause dry mouth.
Medical Treatments
Medical treatments can damage your salivary glands and cause dry mouth, according to the Centers for Disease Control and Prevention. Cancer therapy is a major culprit: Chemotherapy and/or head and neck radiation may dry up your saliva and cause your mouth to get painful and swollen.
Health Conditions
A variety of health conditions can trigger dry mouth. The Mayo Clinic reports that these include diabetes, Parkinson's disease, depression, HIV/AIDS and Sjögren's syndrome. If you suffer from Sjögren's, your white blood cells attack the glands that produce saliva.
Nerve Damage
Xerostomia may result from damage to the nerves that help your mouth experience sensation. This damage can occur from trauma to your head or neck. Your salivary glands may not be hurt, but they can't do their job properly without receiving signals from the nerves.
Smoking
Smoking or chewing tobacco can cause dry mouth. You also may experience dry mouth or a sore throat when you quit smoking. These are among several symptoms of withdrawal when you've been addicted to nicotine.
