Background: Dental and oral health is an important part of body health that is interrelated with each other. Among the oral health problems is dental caries. Efforts to prevent dental caries can be done by improving oral health, one of the safer alternatives to maintain salivary pH is to use herbal ingredients. One of the herbal ingredients that can be used is red ginger (Zingiber officinale var. rubrum). Purpose: Provide information about the effect of red ginger water on salivary acidity degree. Method: This type of research is experimental research with One Group Pre-Posttest Design. The population of this study was all preclinical students of the Faculty of Dentistry, Prof. Dr. Moestopo University (Beragama) with a sample of 16 determined by the Federer formula. The sixteen samples were first measured for salivary pH and then treated by gargling with 10 ml of red ginger water for 30 seconds. After leaving it for 5 minutes, a second salivary pH measurement was taken. The data in this study were analyzed using a parametric test (paired t-test). Results: The mean salivary acidity (pH) before treatment was 6.647 and the mean salivary acidity (pH) after treatment was 7.274. The paired t-test results showed a p-value of 0.000 (<0.05), which means that there is a significant difference between salivary pH before and after exposure to red ginger water. Conclusion: There is a significant effect of red ginger water on salivary acidity (pH).