Patients with xerostomia, or dry mouth, resulting from various causes, are at higher risk for developing caries because of a loss of saliva and its benefits. A loss of saliva increases the acidity of the mouth, which affects many factors that contribute to the development of caries, such as proliferation of acid-producing bacteria, inability to buffer the acid produced by bacteria or from ingested foods, loss of minerals from tooth surfaces and inability to replenish the lost minerals, and loss of lubrication. Currently, a number of new products that can substitute for these functions of saliva or induce production of saliva are available in Canada. Some of these products are reviewed and a protocol for caries prevention in this high-risk population is proposed.