The balance of the microbiota that makes up the intestinal microbiota (species diversity and number) affects mental health, and disorders in these are associated with many diseases and disorders involving the brain and mental health; microbiota disorders of both the affected individual and the mother before and during pregnancy (autism, schizophrenia, anxiety, depression, attention deficit hyperactivity disorder, etc.). The gut and the brain talk to each other in two directions and affect each other (crosstalk, bidirectional communication). This communication and interaction between the gut and the brain, which has important medical consequences, is mediated by four pathways: 1. Neural (neuronal) pathway 2. Neural and hormonal (neuroendocrine) pathway 3. Metabolic pathway 4. Immune (immunological) pathway.