Recent studies1,2 have determined that there is a need for retreatment with isotretinoin after the first course in about 22% to 23% of patients. However, stating that a certain percentage of patients need retreatment with isotretinoin only partly describes the clinical outcome. Many patients experience relapse of their acne, but it is not severe enough to warrant more isotretinoin. The primary purpose of this study was to determine more accurately the percentage of patients who after 1 course of isotretinoin (1) remain clear of their acne; (2) experience a relapse and are treated with topical therapy only; (3) experience a relapse and are treated with oral antibiotics in addition to topical therapy; or (4) experience a relapse and are given a second course of isotretinoin. Factors that might influence the likelihood of relapse were evaluated. Also, an optimum dose was suggested to achieve the lowest recurrence rate.