A child’s immune system is significantly regulated by the gut. Anything which effects the quality of the gut microbiota can effect immunity and the risk of various diseases. Atopic diseases like asthma, eczema and allergic rhinitis and autoimmune diseases like type I DM and multiple sclerosis are associated with disruption of gut immunity. Studies showing benefit from probiotic therapy are limited, but one recent study showed a significant reduction in eczema lasting up to four years of age when both the pregnant mother and after birth the child were treated with a certain strain of lactobacillus. While awaiting more therapeutic studies, we can be sure that a healthy gut microbiota is very important for overall health and that every effort should be made to preserve it. Will next consider microbial effects on digestive issues and metabolic disease.