Cationic peptides are important components of the natural defense of most living organisms against microbial infection. They are expressed in numerous mucosal tissues or by bacteria or their products. They interact with the surface of bacteria, by forming channels in the cytoplasmic membrane and rendering it susceptible to lytic enzymes. In this review we to want to stick out the significance of the antimicrobial peptides, their classification, functions and ability of microorganisms to react faced with, as well as to give a first approach to close related peptides to Streptococcus mutans, since its biosynthesis, mechanism of action and role in oral health are known, we may use this knowledge to obtain synthetic peptides that exert a control against dental caries.