A study was carried out to compare the clinical features of 102 subjects suffering from burning mouth syndrome (BMS) and 43 age- and sex-matched control subjects. In comparison with those in the control group, the BMS subjects reported a significantly higher prevalence of dry mouth, thirst, taste and sleep disturbances, headaches, nonspecific health problems, pain complaints, and severe menopausal symptoms, but no significant differences in other oral or dental features or in the prevalence of candidiasis infection. In addition, there was no hematologic evidence of a nutritional disturbance in more than 90% of the BMS subjects tested, but immunologic abnormalities and an elevation of the erythrocyte sedimentation rate were found in more than 58% and 63% of the BMS subjects, respectively. These findings demonstrate those features which distinguish BMS subjects from age- and sex-matched control subjects but provide no confirmatory evidence for many of the etiologic factors frequently suggested for BMS.