Here we report the effectiveness of various liposome vaccines containing Streptococcus mutans glucosyltransferase (GTF) in protecting against dental caries after oral immunization. Rats were immunized by gastric intubation of the appropriate liposome vaccine at weaning and boosted 3 times. Rats were infected with S. mutans following initial immunization and fed cariogenic diet (Diet 305). Saliva and serum were collected during the study and assessed for antibody activity by enzyme-linked immunosorbent assay. Mandibles were removed on day 47 and assessed for S. mutans levels and then for caries. Animals immunized with sonicated, filtered and microemulsified GTF liposome preparations had decreased levels of dental caries compared with control animals given empty liposomes. Rats given dehydrated/rehydrated or purified liposomal GTF also had significantly less caries than control group (GTF alone). Because of economy, ease of preparation and efficiency in amount of antigen used, filtered, dehydrated/ rehydrated and purified liposomal GTF preparations are most practical for use in further assessing the efficacy of liposomal GTF in oral immunization.