Over the last years, feed additives that support gut health have gained special attention from animal producers worldwide. Tim Goossens and Daniel Ramírez at Nutriad discuss how feed additives do not cure acute bacterial challenges, but prepare the gastro-intestinal tract of animals as well as possible to overcome negative consequences of certain diseases in a later life stage. As many of the effects of feed additives on bacteria are indirect, or modulate their virulence pathways, rather than having a specific bacteriostatic effect, the chance of building up resistance against these components is much less likely.