Over two years 206 neonates received their mothers milk, 308 were given a formula milk. A dip-slide method, well-known from urine diagnostics (Uricult) was used for bacteriological examination. Breast milk in good condition was given untreated to the neonates. The incidence of intestinal infections was much less in babies who received breast-milk. The anti-infective properties of human milk could be demonstrated.