Xerostomia is the subjective, self-reported complaint of a &ldquo\;dry mouth.&rdquo\; Xerostomia and hyposalivation are typically interrelated, with salivary flow reduced by 50%. However, hyposalivation may be absent despite the complaint of xerostomia, and patients may complain of dryness irrespective of the amount of saliva in the mouth. Xerostomia affects about 10% of 30-year-olds and up to 20% of older adults and is commonly associated with medical conditions, medication use, stressful conditions, and hyposalivation. This Quality Resource Guide (QRG) reviews the functions of saliva in maintaining oral health, the prevalence and causes of xerostomia, the symptoms of xerostomia and signs of hyposalivation, the management of symptoms of xerostomia and hyposalivation, and methods to prevent and treat the complications of hyposalivation. Narrative dialogue and concise tables describe the prevalence &amp\; etiology of xerostomia, prescription drugs that may reduce saliva, diseases associated with xerostomia, methods used to recognize the manifestations of xerostomia and hyposalivation, and products and preventive strategies for xerostomic patients. This QRG will serve as an essential resource for the dentist and office staff members, as they assist patients who voice concerns about a dry mouth and manage the direct effect of xerostomia on dental caries.