For alleviation of the distressing symptoms of xerostomia various saliva substitutes are commercially available. The dental literature provides scanty information concerning the subjective relief of oral dryness obtained from the use of these products. Additionally, the rheological properties of the containing polymers, e.g. the viscosity and the lubrication, seem to influence the clinical acceptance of the artificial salivas. Moreover, a demineralizing effect on the dental hard tissues could be observed for some of these products in vitro. A saliva substitute having a remineralizing effect on dentin and enamel, showing preferable rheological properties as well as a long lasting relieve of oral symptoms of mouth dryness seems to be preferable.