The intestinal microbiota behaves like an additional organ and influences our health substantially. Probiotics can positively affect the microbiota and the intestinal immune system. The effectiveness of probiotics in treating diarrhoeal diseases and irritable bowel syndrome is well documented, as is their role in preventing antibiotic-associated diarrhoea and necrotising enterocolitis. Probiotics in baby food can be effective in preventing diarrhoea. In this respect the actual data are scarce, official panels are currently not in a position to issue recommendations.