A research group has developed a new method for studying the functionality of microbiota through metaproteomics. The new method poses broad potential for the study of microbiota on a new, functional level. The characterization of the functionality of gut microbiota is central in the study of human health and disease as well as disease prediction, prevention, and treatment. Previous studies have mainly focused on cataloguing the composition of microbiota, but little is known about the functionality of the human gut microbiota.