Dry mouth can develop as a side effect of certain diseases, medical treatments or medications, according to WebMD. Lifestyle choices or habits, such as chewing tobacco, smoking or sleeping with the mouth open, can also cause dry mouth.
Dry mouth is a common side effect of prescription and over-the-counter drugs, notes WebMD. Medicines used to treat allergies, anxiety, depression, asthma and Parkinson's disease can cause a sticky, dry feeling in the throat or mouth. Dry mouth is also a side effect of multiple diseases, including diabetes, rheumatoid arthritis and HIV/AIDS. Certain medical treatments, such as radiation and chemotherapy administered to the head, neck or throat, are known to reduce the activity of the salivary glands. Dehydration, fever, diarrhea or vomiting are also causes.
If the dry mouth is extreme and caused by a medical condition or medication, it is best to speak to a medical professional for possible solutions. A doctor may prescribe an oral rinse specifically designed to restore moisture to the mouth. WebMD also lists several recommendations for improving saliva flow, including drinking plenty of water, using a vaporizer to add moisture to the air, using an over-the-counter artificial saliva substitute or making a conscious effort to breathe through the nose as much as possible.