In the last decades the prevalence of allergic diseases and eczema raised significantly, and today they are the most common chronic pathologies affecting children. It has been shown that a functional intestinal mucosa provides a defensive barrier to the host against potential dangerous antigens, regulating the tolerance to them. Some inflammatory diseases of the gut weaken the barrier causing an increase in the mucosa permeability and in antigenic transition. As a consequence, there is an aberrant immune response and the release of pro-inflammatory cytokines further compromises the barrier functionality. It has been demonstrated that a correlation between allergy and eczema onset and the intestinal microflora composition exists, and in particular, it has been showed that some microorganisms are able to influence the immune response. For these reasons it has been hypothesized that probiotics may have a beneficial role in preventing and treating allergies and eczema. However, the benefits of this treatment depend on many factors, such as the bacterial strain, the duration of administration, the pathology, the patient characteristics (age, diet, allergy predisposition). The aim of this work was to review the present knowledge about the use of probiotics in allergic diseases and eczema, highlighting their role in the aforementioned pathologies.