We have reviewed the functions of salivary secretions and the major role that saliva plays in maintaining oral homeostasis by protection, repair, and lubrication as well as in the initial phase of digestion. Diseases affecting the salivary glands per se as well as systemic diseases that may alter salivary function were discussed, as were treatments of diseases that may disrupt normal salivary function. Simple yet reliable methods of evaluating salivary function to validate subjective complaints were presented.