The most frequent cause of oral mucosal diseases is idiopathic recurrent aphthous stomatitis (RAS). RAS is a disease characterized by painful and recurrent ulcerations localized on oral mucosa and is affecting up to 10-25% of the population on the world. Local and systemic conditions, genetic, immunological and microbial factors may play a role in the pathogenesis of RAS. Although the etiopathogenesis of the disease is not known, the recent investigations have been focused on Helicobacter pylori (H. pylori) as a causative agent. Aphthous ulcers and H. pylori lesions are similar in histopathological examination. In this study, we aimed to investigate the role of the H.pylori infections on the pathogenesis of IRAS.