Isotretinoin has been a dramatically successful treatment therapy for severe and persistent Acne. Initially it was only used for sever cystic acne, its use has been gradually extended for those with significant but milder acne that will not clear despite persistent use of conventional topical and oral therapies. Isotretinoin has an important role in those with scarring because of their Acne. Most studies indicate a success rate of almost 100% and confirm that approximately two-thirds of patients have no relapse when treatment is discontinued. However, it is not clear whether these figures are correct for the patient types now being treated with Isotretinoin.