Recent studies report that some probiotic strains are able to improve allergic diseases. For this reason, we would verify tolerability and efficacy of a industrial preparation of Lactobacillus paracasei (11,688; Proge Farm, Italy) and Lactobacillus salivarius (11,794; Proge Farm, Italy) and value their "in vitro" immunomodulatory effect. We know that, after birth, there's a persistence of Th2 immune response that predisposes to atopy, whereas commensal bacteria are able to induce a Th1 immune response that counter-balances the original response. The "in vivo" study was set up with the recruitment of 20 atopic pediatric patients treated 30 days with 2 doses of Fiorilac (Sharper, Italy), a preparation of the two strains in the proportion of 1:12. Only one patient referred significant improvements of atopic disease, 19 patients reported a good tolerability to the product and 3 patients had a regularization of intestinal function. Immunological tests showed an increase of Th1 immune response as in CD4+ lymphocytes percentage as of IL-12 and IL-10 cytokines production and a significant increase of natural killer (NK) activity, which predisposes to an active response to viral infections and neoplastic transformations.