To the best of our knowledge, ours is the first study to investigate the effect of eradication treatment of H. pylori on mRNA and protein expression levels of inflammatory mediators (TNFA, IL6, IL1B, IL12A, IL2 and TGFBRII) as well as the interaction with miRNAs involved in regulation of inflammation and tumorigenesis processes, such as miR‐103, miR‐181c, miR‐370, miR‐375 and miR‐223 in patients with chronic gastritis and infected by H. pylori. This evidence concerns the gene IL12A and chronic gastritis.