THE PRESENT INVENTION RELATES TO THE USE OF A BIFIDOBACTERIUM STRAIN FOR THE PREPARATION OF COMPOSITIONS, IN PARTICULAR OF AN INFANT FORMULA, INTENDED FOR THE PREVENTION AND/OR TREATMENT OF ALLERGIC-TYPE MANIFESTATIONS. THESE COMPOSITIONS ARE OBTAINED FROM A BIFIDOBACTERIUM CULTURE, WITHOUT HYDROLYZING MILK PROTEINS. THE BACTERIA, WHICH PREFERABLY BELONG TO THE SPECIES BIFICIOBACTERIUM BREVE, MAY BE KILLED OR REMOVED FROM THE COMPOSITION DURING THE PROCESS.