This study examined the relationship between stimulated salivary flow rate and oral health status in an adult population. Multinomial multivariate logistic regression analysis was used to examine the associations of salivary flow rate with dental caries status and periodontal status at the individual level among 2,110 Japanese adults with ≥10 teeth. Then, a spline model was used to examine the nonlinear relationship between salivary flow rate and teeth with dental caries or periodontal disease in multilevel analysis. Odds ratios were calculated for a 1.0-mL/min reduction in salivary flow rate at a point. After adjusting for confounding variables, participants with a flow rate ≤3.5 mL/min had significantly higher odds ratios for high caries status, and participants with a flow rate ≤1.4 mL/min had a higher odds ratio for broad periodontal disease, than did those with a flow rate >3.5 mL/min. In spline models, the odds ratio for teeth with dental caries or periodontal disease increased with reduced saliva secretion. The present findings suggest that decreased saliva secretion affects both dental caries and general periodontal health status.