A randomized trial in babies less than 32 weeks gestation and less than 1500 grams compared the use of probiotics to placebo. Over 1000 babies were studied. Overall breast milk usage rate was high (>95%) in both arms. Babies in the probiotic arm of the trial received a combination of Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis. The frequency of the primary outcome (late-onset sepsis) was not significantly different in the two groups. Neither was mortality. However infants receiving probiotics had a lower rate of Stage 2 of higher NEC (2% versus 4.4% in controls).