Saliva is a promising option for diagnosing certain disorders and monitoring the evolution of certain pathologies or the dosage of medicines or drugs. Its advantages as a diagnostic tool include its being easy to obtain and the positive correlation between many parameters in serum and saliva. Saliva plays an essential r__ampersandsignocirc;le in maintaining the integrity of the oral structures, in personal relationships, in the digestion and in controlling oral infection. Human secretory leukocyte protease inhibitor is a cationic protein in saliva has been found to be the most potent anti-HIV-1 factor among several innate inhibitory molecules namely, virus-specific antibodies, mucins, and thrombospondins, identified and purified from saliva. This review includes the role of slpi as a anti HIV factor, there by reducing the risk of oral transmission of HIV and also antiprotease, bactericidal and antifungal activity are also discussed.