The mouth, like other areas of the digestive tract, possesses a natural microflora, the presence of which confers several beneficial properties to the host. However, in the absence of adequate oral hygiene, dental plaque can accumulate beyond levels compatible with oral health. This leads to shifts in the balance of the predominant bacteria away from those associated with health; such shifts can predispose a site to caries or periodontal diseases. Treatment should be designed, therefore, to control rather than to eliminate dental plaque. Possible strategies to maintain the stability and beneficial properties of the natural oral microflora include the stimulation of saliva flow for an extended period directly after a meal, the avoidance of fermentable carbohydrates during between-meal periods, and improvements to oral hygiene, for example, by using products containing antiplaque or antimicrobial agents.