Twenty-one patients with dermatitis herpetiformis have been on a gluten free diet regularly followed up for at least one year (mean four years). Eighteen patients had a 'flat' mucosal appearance (grade III), one patient had moderately severe mucosal abnormality (grade II), one patient had mild mucosal abnormality (grade I), and one patient had a normal mucosal appearance (grade O). On the diet, 10 patients had no skin rash and took no dapsone, seven patients controlled the skin rash on a lower dose of dapsone, and four noticed no improvement. There was no correlation between pre-diet jejunal morphology and response of the skin. A repeat jejunal biopsy, on the gluten free diet, was possible in 15 patients. While all those with skin improvement showed some improvement in jejunal morphology, there was no association between the degree of skin improvement and the degree of recovery of the jejunal mucosa.