The individual daily intake of gluten was calculated in 45 patients with dermatitis herpetiformis (DH) on the basis of a depth interview about food habits. Gastric and small intestinal morphology and function were studied concurrently. Mean daily gluten intake was estimated to be 15 g, a figure which corresponds well to the average gluten intake in Sweden. There was a significant correlation between the degree of morphological mucosal changes of the small intestine and the quantity of gluten ingested. All patients with jejunal villous atrophy consumed more than 10 g gluten daily and all but one patient with normal jejunal villous structure had a gluten intake of less than 10 g/d. The findings suggest a dose-dependent effect of gluten on the intestinal mucosa. Conversely, the daily gluten intake was not correlated to gastric morphology, gastric acid secretion, serum gastrin levels or serum parietal cell antibodies. Patients with reduced ability to secrete gastric acid did not differ from the remaining patients in this respect. Whereas the coeliac-like enteropathy in DH seems to be caused by ingested gluten, the frequently occurring achlorhydric atrophic gastritis must be assumed to be of different immunopathogenesis.