Recent studies have confirmed immunomodulatory and anti-inflammatory properties of probiotics. There are clinical evidences suggesting that probiotics and prebiotics treatment is effective and had a protective effect in the development of atopic dermatitis and the mechanism may be related to local effect on the gastrointestinal tract. About the effect of probiotics on the allergic airway response, the beneficial effects seem to be strain specific, and other studies will be needed to understand the mechanisms involved. Recent data suggests that probiotics may have immunomodulatory effects on vaccine responses, but the significance and clinical relevance of this need to be determined too.