This double-blind study determined whether daily bathing with an antibacterial soap would reduce the number of Staphylococcus aureus on the skin and result in clinical improvement of atopic dermatitis. For 9 weeks, 50 patients with moderately severe atopic dermatitis bathed daily with either an antimicrobial soap containing 1.5% triclocarban or the placebo soap. They also used a nonmedicated moisturizer and 0.025% triamcinolone acetonide cream as needed, but the availability of the corticosteroid cream was discontinued after 6 weeks. The antimicrobial soap regimen caused significantly greater improvement in the severity and extent of skin lesions than the placebo soap regimen, which correlated with reductions both in S aureus in patients with positive cultures at baseline and in total aerobic organisms. Outcome measures included reductions in S aureus, total aerobic organisms, and dermatologic assessments. Overall, daily bathing with an antibacterial soap was well tolerated, provided clinical improvement, and reduced levels of skin microorganisms.