Background: Recurrent aphthous stomatitis (RAS) is a common disease characterized by repeated formation of non-contagious and benign oral ulcers. It is triggered by different factors and its cause is not completely understood. This study aimed to evaluate the role of serotonin in the patients with RAS, compared to that in the control subjects. Subjects and Methods: Present study involved 100 participants of which 50 subjects diagnosed with RAS and the others without (healthy controls). Blood samples obtained from participants for serum serotonin investigation by enzyme linked immunosorbent assay. Results: Serum serotonin concentrations were significantly (P < 0.05) lower in patients with RAS (mean ± standard deviation [SD]; 5.737±5.007) compared to control group (mean ± SD; 8.709±5.670). Conclusion: Serum serotonin decreased in Iraqi patients with RAS compared to controls. RAS is one of the significant variables that may relate to the low serum serotonin concentrations.

Recurrent aphthous stomatitis (RAS) is a common disease characterized by a repeated formation of non-contagious and benign oral ulcers. The cause for this condition not completely understood but it involves a T cell-mediated immune response initiated and triggered by different factors. The understanding of the pathogenesis of the disease is essential to improve the plan of management. Objective: This study aimed to identify the correlation between the blood levels of tumour necrosis factor-alpha (TNF-?) levels and the development of RAS. Subjects and Methods: Present study involved 100 participants of which 50 subjects diagnosed with RAS and the others without (healthy controls). Blood samples obtained from participants and used for TNF-? investigation by enzyme linked immunesorbent assay. The data collected was statistically analysed. Results: Serum TNF-? concentrations were significantly (P < 0.05) higher in patients with RAS (mean ± standard deviation [SD]; 104.27 ± 41.63) compared to control group (mean ± SD; 85.30 ± 38.72). Conclusions: Serum TNF-? is increased in Iraqi patients with RAS compared to controls. RAS is one of the significant variables that relates to high TNF-? serum concentration.