H. pylori is a bacterium that is found in the stomach which, along with acid secretion, damages stomach and duodenal tissue, causing inflammation and peptic ulcers. Although most people will never have symptoms or problems related to the infection, they may include: dull, ‘gnawing’ pain which may occur 2-3 hours after a meal, come and go for several days or weeks, occur in the middle of the night when the stomach is empty and be relieved by eating; loss of weight; loss of appetite; bloating; burping; nausea; vomiting.