The role of probiotics in gut health has garnered significant attention over the past few decades, with numerous studies highlighting their potential benefits in maintaining gut microbiota balance, enhancing immune function, and preventing or treating gastrointestinal disorders. Probiotics, defined as live microorganisms that confer health benefits to the host when administered in adequate amounts, have been shown to influence gut health through various mechanisms. This comprehensive review examines the current evidence on the efficacy of probiotics in promoting gut health, explores their mechanisms of action, and discusses future directions for research and clinical applications. Key areas of focus include the impact of probiotics on gut microbiota composition, their role in managing gastrointestinal diseases such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), and their potential in modulating immune responses and metabolic functions. The review also addresses the challenges and limitations in probiotic research, including variability in strains, dosing, and individual responses, and highlights the need for standardized guidelines and personalized approaches in probiotic therapy.