Fifteen children with atopic dermatitis who had Bifidobacterium-deficient microflora were selected for this study. Eight subjects in the bifidobacteria-administered group were given oral administration of lyophilized bifidobacteria (Bifidobacterium breve M-16V strain). The changes in fecal microflora and clinical symptoms were compared with the control group. In the bifidobacteria-administered group, the proportion of Bifidobacterium in the fecal microflora was increased (P=0.0173) and the proportion of aerobic bacteria was decreased (P=0.0499) after 1 month of administration. Furthermore, significant improvement of allergic symptoms (P=0.0176 in cutaneous symptom score, P=0.0117 in total allergic score) was also observed in the bifidobacteria-administered group. The tendency of allergic symptom improvement in the bifidobacteria-administered group was remarkable compared with the control group; however there was no correlation between changes in fecal microflora and allergic symptoms.