Saliva plays an important role in oral health, providing protection, lubrication, and aiding functions like chewing and swallowing. Xerostomia, or dry mouth, can occur when saliva production is reduced by 40-50% and causes symptoms like a dry feeling and increased risk of issues like cavities. Xerostomia can be caused by conditions that affect the salivary glands like Sjögren's syndrome, or indirectly by treatments like radiotherapy or various medications. Left untreated, xerostomia can lead to complications like increased risk of oral infections. Treatment options include staying hydrated, using saliva substitutes, avoiding irritants, and good oral hygiene.