Summary: The discovery of the relationships and connections in the microbiota‒gut‒brain axis and the relationship between the intestinal microflora and diseases of the central nervous system created a space for research in this area. The intestinal microflora that develops in the postpartum period has a significant impact on the development and maturation of the nervous, immune and endocrine systems. Influencing the intestinal flora by administering certain probiotics in early childhood to a selected group of children may be a method of preventing neurodevelopmental diseases. Modification of the intestinal flora in adults has a positive effect on the functioning of the gastrointestinal tract. There are preliminary scientific reports suggesting that interference with the composition of the intestinal microbiota supports the treatment of anxiety and depression disorders, early stages of Alzheimerʼs disease and Parkinsonʼs disease. Probiotics that affect the gut‒brain axis, human behavior and brain functions are called psychobiotics.