A new study at the University of Chicago has determined that restoring a single microbial species—Bacteroides sp. CL1-UC (Bc)—to the gut microbiome at a key developmental timepoint can prevent antibiotic-induced colitis in a mouse model of the condition. The results, published on June 7 in Gastroenterology, have major implications for humans dealing with inflammatory bowel disease (IBD), and underscore the impact of early childhood exposures on health throughout the lifetime.