Objectives To characterize demographic, clinical and serological parameters in recurrent aphthous stomatitis ( RAS) patients and analyse their association with serum immunoglobulin E ( Ig E) levels. Subjects and Methods Forty-nine patients with RAS responded to a questionnaire that included demographic background, stress status, smoking habits, history and course of RAS episodes. They were also subjected to relevant laboratory tests, including determination of serum Ig E levels. Results A familial history of RAS was reported by 47.9% of the patients, stress in the previous year by 51.1% and smoking by 18.4%. Non- Caucasian origin, familial history of RAS, stress and smoking were associated with increased severity of RAS episodes. Haematological deficiencies were observed in 18.7% of RAS patients. Average Ig E levels were increased and were significantly associated with younger age, ≤12 years of schooling, female gender, RAS episode frequency of every 2 weeks , early onset of RAS episodes and elevated C reactive protein levels. Conclusion Immunoglobulin E levels may be considered as part of the RAS patient's work-up. Further research is needed to identify biological mechanisms that account for the observed associations. [ABSTRACT FROM AUTHOR]