Many elderly patients have various health problems and are susceptible to recurrent fever. We examined the influence of oral health on the febrile status of 271 long-term hospitalized elderly patients over 1 year. In dentate patients, those with > or =20 teeth had a significantly higher risk for fever than those with 1-9 teeth; multivariate logistic regression analysis: odds ratio (OR)=5.44, 95% confidence interval (CI)=1.37-21.66. In edentate patients, those with moderate or much tongue plaque had a significantly higher risk for fever than those with no or slight tongue plaque; multivariate analysis: OR=5.14, 95% CI=1.77-14.88. These results suggest that oral health status related to febrile status differs between dentate and edentate patients in the elderly population.