Probiotics have been proven to improve intestinal health by restoring epithelial function, maintaining mucosal immunological homeostasis, and suppressing pathogenic bacteria. Recent discoveries reveal a method for identifying previously unknown probiotic-derived soluble components as potential probiotic action mechanisms. The symbiotic link between the gut microbiota and the host creates an ecosystem that supplies the microbiota with a nutrient-rich and physiologically friendly environment while also providing significant benefits to the host in terms of nutrition acquisition and energy balance. In adulthood, metabolites and functional factors derived from the gut microbiota have been shown to have a significant impact on the structural and functional maturation of the gastrointestinal tract, induction of immunotolerance, neurodevelopment and homeostasis of intestinal epithelial cells, and immune and nervous system functions in humans and animal models. Probiotics' functions are thought to be linked to host genetics and environmental factors because they are components of the gut microbiota.