pH of saliva is a component that contributes to oral pH. Pathogenic bacteria in the oral cavity ferment sugars into lactic acid which will decrease the acidity of the mouth causing demineralization of tooth enamel. Decrease in saliva pH can be prevented chemically by giving a sense stimulus. Black cumin has a chemical content of nigelin (bitter substance), which causes a bitter taste that can stimulate the speed of salivary secretion that affects the degree of purity (pH) in the mouth. The purpose of this study to determine the effect of drinking boiling water black cumin to saliva pH on PKK mothers. This type of research is descriptive quantitative. The method used quasi experiments, and research design used pre and post experimental design. The sample of this research are PKK mothers RW 01 in Procot Village, Slawi District, Tegal Regency with 24 samples. Salivary pH measurements were performed before and after treatment to see changes in salivary pH by using pH strips. Data analysis used quantitative descriptive method. The results obtained the influence of water boiled black cumin with the average before rinsing water boiled black cumin 6.4 (neutral) and average after rinsing boiled water black cumin 7.0 (base). Increased salivary pH after rinsing can neutralize the acidic state that triggers dental caries. To maintain oral hygiene is recommended people who have cavities to gargle using black cumin boiled water as a traditional mouthwash.