The digestive system has an explicit role in decomposing nutrients into energy and other necessary substances required by the body. The gastrointestinal tract contains a complex set of different microorganisms. It is considered the most dynamic and active organ in the body from a biological perspective. The environmental condition and daily diet are principal parameters that significantly influence the composition of gut microbiota. From birth to middle age, it undergoes significant changes. Several factors, such as maternal microbiota, birth status (natural, cesarean section), postpartum nutrition practices, microbial infections, overuse of antibiotics, diet (highly processed, low fiber), chronic diarrhea, and stress in life, have a significant effect on the gut microbiome. All of these factors lead to impaired bowel function and health. One of the most important strategies for overcoming dysbiosis conditions and establishing eubiosis conditions is the employment of foods containing probiotic, prebiotic, and postbiotic ingredients. Hence, this chapter provides a review of the concept and health-promoting issues regarding probiotics and prebiotics, with a focus on their biological role in the establishment of health.