The conventional treatment of acne is relatively free of serious side-effects, so much so that it is most unusual for a patient to discontinue  therapy for this reason. Although the treatment given to the more difficult cases produces more problems, cessation of this therapy also is a rare event.  This chapter details the side-effects of the most commonly available  treatments. but with less frequency. With continued treatment the dermatitis associated with topical therapy usually  improves - probably because the patient knows better how to use the treatment.