Potentiation of the host immune system has been considered, in addition to non-immunological measures as a means of preventing the development of dental caries. Because specific antibodies in the oral cavity are derived from two sources--the salivary glands that produce secretory IgA, and the general circulation that provides IgG antibodies--immunization efforts in various experimental models have been aimed at stimulating either of these compartments. Streptococcus mutans, the principal cariogenic microorganism, and various cell wall components and extracellular enzymes have been used as antigens. In experimental animals, systemic or oral routes of immunization have induced protective IgG or IgA antibodies respectively, but the mechanisms of protection have not been clearly established. The possibility of stimulating a generalized secretory immune response by oral ingestion of antigens may have advantages for the induction of protective antibodies in humans, because parenteral immunization routes may not be readily acceptable for reasons discussed in this review. Nevertheless, further experimental work is required to select appropriate antigens, and to determine optimal doses and immunization schedules for inducing antibodies at an age that is critical in the development of dental caries.