In order to determine the efficacy and tolerance of two topical antiseptics, chlorhexidine vs KMn04 (diluted at 1:20,000), we compared their bacteriological and clinical effects in a randomized trial on 20 children with Atopic Dermatitis (AD) treated with topical steroids (desonide). After treatment, a clinical improvement was noted in the two groups, though without statistical differences. In vivo: Before treatment, Staphylococcus aureus (S.A.) density was high and predominant in both groups. After treatment, the decrease in S.A. was greater in the chlorhexidine group than in the KMn04 group, without significant difference. In vitro: At the clinical dilution used, there was a statistical difference (p < 0.05) between the number of killed bacteria in the chlorhexidine group (-3 log) and the number in the KMn04 group (-1 log). This study confirms the role and importance of the choice of a topical antiseptic in the treatment of AD.