However, the effect of H. pylori eradication on the ghrelin concentration is a more complex issue [5, 6], and it seems that some factors such as the grade of gastritis caused by H. pylori, duration of the infection, the strain of H. pylori, hormonal factors, nutritional changes, etc. may affect the ghrelin level [5, 6, 27]. The gene discussed is GHRL; the disease is gastritis.