Prophylaxis against *Lawsonia intracellularis* (PIA, etc.) is of profound importance for gut health in pigs. Scientific data and field observations demonstrate significant benefits regarding mortality rates, growth, and feed conversion efficiency, as well as the resulting economic outcomes. Furthermore, the need for antibiotic treatment is reduced, and nitrogen and phosphorus emissions—along with the carbon footprint—can be sustainably improved. Recent observations further highlight the importance of a protected gut by demonstrating a reduced incidence of tail lesions and improvements in herds simultaneously affected by *Salmonella*.