Atopic dermatitis (AD), a chronic and relapsing inflammatory skin disease, is associated with elevated IgE levels and Th2 responses. It is currently believed that non-pathogenic bacteria modulate intestinal immune responses avoiding the development of allergic diseases. However, effects of oral probiotics on AD could not be reproduced in all studies and direct immuno-modulation of the skin associated immune response by non-pathogenic bacteria has not been investigated so far. We therefore performed a double blind placebo controlled clinical study on the effects of an ointment containing 5% extracts of the non-pathogenic bacteria Vitreoscilla filiformis on AD. Seventy-five AD patients (6-70 years of age) were randomized to receive either Vitreoscilla filiformis ointment 5% or vehicle ointment daily for 30 days. Efficacy evaluations, including the "Score of Atopic Dermatitis" (SCORAD), transepidermal water loss, assessement of microflora, and the patient assessment of itch and loss of sleep occurred at baseline, day 15, and day 29.