Several salivary proteins are involved in the antimicrobial defence within the oral cavity, and are able to eliminate or inhibit a great number of microorganisms that enter the body via the oral cavity. Thus changes in the composition of saliva may not only affect peoples oral health, but also have consequences for their general health. Based on salivary proteins, antimicrobial peptides have been synthesized. Potentially, these could be used as a new class of antibiotics. The antimicrobial peptides are hardly cytotoxic to human cells and do not evoke any or only very little resistence in microorganisms.