H. pylori is the most common cause of nonerosive nonspecific gastritis; however, its main importance has been as a marker in research studies of eradication in relation to duodenal ulcer relapse. In developed countries, the most common histologic pattern appears to be that of a mild superficial chronic active gastritis. When H. pylori is present in the antrum it is virtually always present in the body as well, although inflammation in body mucosa is usually milder than that in the antrum. The organisms do not overlie areas of intestinal metaplasia; thus, H. pylori is commonly absent in individuals with diffuse intestinal metaplasia as seen in severe atrophic gastritis. Studies of H. pylori gastritis have been of enormous value in research studies; however, in the clinical management of the individual patient there is only limited value to documenting the presence, character, and severity of H. pylori gastritis.