Streptococcus mutans is a common principal causative agent of dental caries. In this communication, we describe that the antibodies raised against purified dextransucrase effectively inhibited the growth of S. mutans. The purified enzyme showed 58-fold enrichment, 17.5% yield and a specific activity of 3.96 units/mg protein. Purified IgG fraction of the antibody showed significant affinity with the antigenic protein. Immunotritation of the enzyme with dextransucrase antibody showed a gradual increase in inhibition of dextransucrase activity. The growth of S. mutans was also inhibited by 85% in the presence of 28 mu g of IgG fraction of the antibody. Antibodies also impaired glucosyltransferase activity (72.8%) and biofilm formation by 92.6% in S. mutans. Western blot analysis revealed no cross reactivity with the various tissues of mice, rat, rabbit and humans. Dot blot analysis showed little reactivity with Lactobacillus acidophilus and Staphylococcus aureus and there was no reactivity with other bacterial strains like Enterococcus faecalis, Escherichia coli and Salmonella typhimurium. These findings suggest that antibody raised against dextransucrase exhibit inhibitory effects on the growth of S. mutans and biofilm formation with no reactivity with various mammalian tissues, thus it could be an effective anticariogenic agent.