The ability of an oral rinse preparation, containing an admixture of the oxohalogen oxidants chlorite anion and chlorine dioxide, to diminish salivary levels of Streptococcus mutans, lactobacilli and Candida albicans was investigated in a group of 33 dental patients. Patients underwent oral rinsing episodes with the above product (20 ml for a period of 60 seconds, three times daily) for a total of 14 days, and subsequently repeated this exercise with mineral water in place of the oral rinse formulation. A group of 10 dental student volunteers, conducting the same oral rinsing regimens with mineral water in place of the oral health care product, served as a control group. Salivary microorganism levels were determined both prior and subsequent to the above trial period. The results demonstrated that biocidal oxohalogen oxidants present in the oral rinse formulation tested gave rise to a substantial reduction in salivary S. mutans and lactobacilli levels (p < 0.001 and 0.005, respectively), although the decrease observed in C. albicans failed to reach statistical significance. As expected, mineral water employed as an oral rinsing system by the same group of patients, or the student control group, exerted no influence on the salivary levels of each of these microorganisms. The therapeutic, microbial and biochemical ramifications of the results obtained are discussed.