[Eosinophils in stool smear in normal and milk-allergic infants]

Stool smears of newborn infants were investigated sequentially from birth through 6 months of life in order to study relation between appearance of eosinophils in stool and feeding of babies. In babies born to non-atopic parents, eosinophils appeared in stool smear soon after start of feeding, but disappeared in a short time. Eosinophils were found irrespective of types of feeding, i.e., breast feeding, powdered milk or amino acid formula. There was tendency of sustained presence of eosinophils in stool smears in babies born to severe atopic parents. These results suggest that appearance in stool of eosinophils does not necessarily mean allergic reaction to ingested foods and need attention in diagnosing milk allergy. Mechanisms of appearance and function of eosinophils in stool in normal babies may differ from those in pathological situations and need further detailed investigation.