Even short, single antibiotic courses given to young animals can predispose them to inflammatory bowel disease (IBD) when they are older, according to new researchers. The study provides further evidence supporting the idea that the use of antibiotics in children under 1 year old disrupts the intestinal microbiota – the trillions of beneficial microorganisms that live in and on our bodies – that play a crucial role in the healthy maturation of the immune system and the prevention of diseases.