As animals living amongst microbes, we need to distinguish between microorganisms that are benign or beneficial versus those that are pathogenic. Our health depends on a maintaining a functional microbiome while avoiding the propagation of pathogenic microbes. As microbial hosts,we therefore must have mechanisms to influence which microbes stay and which must go.To this end, our group is focusing on a prominent feature of the cell’s exterior—the carbohydrate coat. From humans to fungi to bacteria, virtually all cells on Earth possess a carbohydrate coat. One important role of this coat is to serve as an identification card. Our group has been examining the role of carbohydrate-binding proteins, lectins, in influencing our microbiota and in immune defense. This seminar will focus on understanding the basis of carbohydrate-protein interactions and how they are used to influence microbes. We envision that our findings can lead to alternative means to combat pathogens, methods for rapid approaches to ID microbiota, and the development of new strategies to regulate microbiome composition to promote human health.