Xerostomia means: Xerostomia is dry mouth. Sjogren’s syndrome and systemic lupus-erythematosus can all be linked to Xerostomia. It can also be caused by poor hygiene and medication. Inadequate function of salivary glands such as parotid and sphincter glands can cause Xerostomia. The treatment involves water intake, artificial saliva and excellent dental care. If left untreated, dryness can cause tooth decay and thrush.
(in Medical Dictionary)

What else does Xerostomia mean?

Dryness abnormally in the mouth.
(in Merlin Dictionary)