Introduction The microbiota-gut brain (MGB) axis is the bidirectional communication between the intestinal microbiota and the brain. An increasing body of preclinical and clinical evidence has revealed that the gut microbial ecosystem can affect neuropsychiatric health. However, there is still a need of further studies to elucidate the complex gene-environment interactions and the role of the MGB axis in neuropsychiatric diseases, with the aim of identifying biomarkers and new therapeutic targets, to allow early diagnosis and improving treatments. Areas covered To review the role of MGB axis in neuropsychiatric disorders, prediction and prevention of disease through exploitation, integration and combination of data from existing gut microbiome/microbiota projects and appropriate other International “-Omics” studies. The authors also evaluated the new technological advances to investigate and modulate, through nutritional and other interventions, the gut microbiota. Expert opinion The clinical studies have documented an association between alterations in gut microbiota composition and/or function, whereas the preclinical studies support a role for the gut microbiota in impacting behaviours which are of relevance to psychiatry and other central nervous system (CNS) disorders. Targeting MGB axis could be an additional approach for treating CNS disorders and all conditions in which alterations of the gut microbiota are involved.