Two patients with clinically and histologically typical dermatitis herpetiformis showed a dramatic clearing of their skin lesions in association with an oral dose of 4 g of cholestyramine three times a day. Reappearance of the lesions occurred on the discontinuance of the therapy, followed by remission on resumption of cholestyramine. It is postulated that the non-absorbable anion exchange resin, cholestyramine, may have bound and hence blocked absorption of an unidentified compound (possibly gluten, iodine, or endotoxin) critical to the pathogenesis of dermatitis herpetiformis.