Long-term antibiotic therapy of acne does not imply that the drugs are slow to produce an effect; actually, the patient may improve quickly, but when their use is stopped the acne relapses. The same is true of dermatitis herpetiformis, which, however, is usually far more chronic than acne. In most series of cases where accepted methods of treatment are used, 50% to 75% of acne patients improve substantially within 6 to 9 months. The rest are more resistant. It is this latter group with which we are here concerned in this paper. The patients in it remained from an original 132 whose therapy was begun with antibiotics. Those not included for further consideration went on to sufficient improvement to permit withdrawal of the antibiotic. Materials and Method All patients were initially given 1,000 mg. tetracycline* (4 capsules) daily, and no other therapy was given once the tetracycline regimen was begun.