Background:Helicobacter pylori (H.pylori) is a major human pathogenic bacterium in gastric mucosa.MicroRNAs (miRNAs) have recently emerged as a new class of novel regulators of gene expression.The regulatory role of miRNAs in response to H.pylori infection is just beginning to be explored.Methods:The expression of miR-146a was analyzed in gastric mucosal tissues from H.pylori-induced chronic gastritis by quantitative RT-PCR.Promoter analysis and inhibitor experiment were used to investigate the pathway involved in the induction of miR-146a.The potential target of miR-146a was identified by luciferase assay and western blot.Examination of miR-146a function was performed by overexpression and inhibition of miR-146a.