Dry mouth, or xerostomia, occurs when there is not enough saliva or when saliva becomes very thick. This can be a side effect of radiation therapy to the head and neck, it can also be due to some types of chemotherapy, certain drugs, or dehydration. The glands that produce saliva may become inflamed or damaged, resulting in decreased saliva production or the saliva becoming very thick and sticky. The degree of dryness may be mild or severe depending on the cause and the lifestyle of the patient. Dry mouth and thick saliva can increase the risk of cavities and oral infections in patients suffering from this type of syndrome and particularly cancer patients. Other habits like smoking, chewing tobacco, and drinking alcohol can make mouth dryness even worse.