The reducing ability of saliva is decreased with donor age as indicated by cyclic voltammetry measurements of saliva. It has been shown that saliva possesses a strong reducing power that is influenced by the induction of oxidative stress. The exact capacity of saliva to cope with oxidative stress has never been studied in detail. We used a new approach to detect the role of oxidative stress on saliva. This approach included the detection of the total reducing capacity of the saliva without determination of the exact concentration of a specific reducing compound present in the saliva. Induction of oxidative stress resulted in a significant change in the reductive capacity detected. Measurements of the reducing potential of saliva revealed that there is a correlation between the donor age and the reductive capacity observed. Also, saliva obtained from donors in various disease states have shown a significant change in the potential recorded, as compared to controls. The possible use of this method as a diagnostic tool in various diseases is discussed.