A bifidus factor (bifidogenic factor) is a compound that specifically enhances the growth of bifidobacteria in either a product or in the intestines of humans and/or animals. Several products have been marketed as bifidogenic factors, such as several prebiotics and methyl-N-acetyl D-glucosamine in human milk. A bifidus factor (bifidogenic factor) is a compound that specifically enhances the growth of bifidobacteria in either a product or in the intestines of humans and/or animals. Several products have been marketed as bifidogenic factors, such as several prebiotics and methyl-N-acetyl D-glucosamine in human milk.