Book excerpt: This book covers all aspects of probiotic bacteria and their metabolites, as well as their role and significance in human and animal health. Given the role of probiotic bacterial strains in the production of short chain fatty acids, butyrate etc probiotics may be considered as an alternative approach for the prevention or treatment of intestinal dysbiosis, cancers, cardiovascular diseases, hypertensions. Additionally, the significance of probiotics added in aquaculture systems for improving health, performance and growth of aquatic organisms has been highlighted. In this book, the multi-functional role of probiotics and their post-biotic metabolites in improving overall health status of man and animals, is discussed. It is a comprehensive compilation useful for researchers, academics, veterinarians and students in the field of microbiology, food technology and biotechnology.