Fuente: Asqueous Extraction Byproducts Oligosaccharides are the group of carbohydrates containing 2–10 sugar units. These are nondigestible in the small intestine and are utilized as a food source by gut microflora in the colon. They also help in restoring a healthy gut by selectively supporting the growth of one or more health-promoting microorganisms. A healthy gut improves digestion, immunity, and prevents lifestyle disorders such as diabetes, obesity, and cardiovascular diseases. This has increased the demand of oligosaccharides and they are now widely used in functional foods and nutraceuticals. This chapter discusses the types of oligosaccharides, their sources, and methods of isolation, and characterization.