Dental caries is occurred due to an imbalance between demineralization and remineralization. The mineral loss has resulted from acids produced by bacteria in biofilms. Several studies showed that mutans streptococci are predominant bacteria playing in this important role. Therefore, removal of these bacteria is one of the caries prevention strategies. Current antimicrobial agents have broad-spectrum activity. They are effective against wide-range of bacteria leading to opportunistic infections. This fact prompts an interest in searching a new approach that selectively eliminates cariogenic bacteria. Peptidoglycan hydrolase is an enzyme that degrades peptidoglycan, the major component of the cell wall of gram positive bacteria. With potential to eliminate bacteria including antibiotic resistant strains, the enzymes have been studied by several research groups. Automutanolysin is a peptidoglycan hydrolase produced by Streptococcus mutans. The enzyme has been interesting because it shows substrate specificity against mutans streptococci. Moreover, the previous study showed that the enzyme has ability to lyse clinical isolations in biofilm form. All data together indicates the possibility in developing automutanolysin as an alternative approach in caries prevention.