Galactooligosaccharide is one of prebiotics materials containing galactose and used mainly for infant formula products because some components of galactooligosaccharide are recognized as human milk oligosaccharides. Some studies showed that galactooligosaccharide has the outstanding physiological functions such as boosting immune system, improving skin conditions, and some others. And it has a role of making good intestinal microflora based on prebiotics effects. In conclusion, galactooligosaccharide is expected to be used for food materials such as functional beverages and dietary supplements, based on various physiological functions as well as physical stability.