When mothers wanted to shift from breast milk to infant formulae, babies were randomly assigned to receive a fermented or a standard formula. Biological and clinical investigations were achieved at baseline (V1), and after one (V2) and three months (V3) of consumption of study formula. Intestinal microbiota was assessed by using culture-dependent techniques.

Inclusion Criteria:

• Eutrophic infants, (± 2SD), healthy, male or female, of 2 months of age (± 1 week)
• Born at 37 weeks of amenorrhea or more
• Exclusively breastfed since birth
• Written informed consent given by both parents (or tutors) for study participation
• Parents (or tutors) agreeing on the follow-up by one of the study investigators

Exclusion Criteria:

• Infant with congenital or acquired immunodeficiency, whatever the aetiology
• Infant with a significant metabolic, organic or bowel disease which could interfere with the results of the present study,
• Infant with congenital and/or chromosomal malformation,
• Infant having received antibiotic therapy within the 3 weeks before the inclusion visit
• infant receiving a treatment susceptible to interfere with the measure of study parameters
• Antibiotic therapy per/pre/post partum > 48 h
• Infant needing the prescription of a specific milk (HA, without cow milk)
• Infant in a situation which could interfere with an optimal participation to the study, or which could represent a risk for the infant, according to the investigator.