Gastric mucosal histology and function were evaluated in 57 Italian subjects with dermatitis herpetiformis (DH), by means of multiple endoscopic biopsies, gastrin and pepsinogen I (Pg I) serum levels, and parietal cell antibodies (PCA). One hundred and forty-nine patients with nonulcer dyspepsia served as reference population for the prevalence of atrophic gastritis of the body. Seventeen DH patients (30%) and 23 controls (15.4%) showed atrophic gastritis of the body mucosa (p less than 0.05). Nine of the DH patients with atrophic gastritis of the body also had atrophic changes in the antrum. Six patients, all with severe atrophic gastritis, had high gastrin levels and PCA; five of these six also had low Pg I levels. We found an increased prevalence of abnormal indirect function tests among patients with atrophic gastritis is due to the younger age of the patients in our series. Thus, atrophic gastritis can be detected early on a histologic basis, but functional impairment occurs later, as the mucosal damage increases in severity.