Infantile asthma presents a major therapeutic challenge to the practicing physician. The typical infant with asthma is a 14-month-old boy with recurrent episodes of wheezing since the age of seven months. Nasal eosinophilia is found less often than in older allergic children; however, 47 percent of infants with asthma will have either peripheral blood or nasal secretion eosinophilia to aid in the recognition of their atopic diathesis. The younger the infant (both at age of onset and at age of evaluation) the more likely are foods to be important factors in his allergic respiratory disease. His disease is unlikely to interfere with growth during infancy but may do so later in life. Hyposensitization is more likely to be required later in childhood if he does not respond to dietary manipulation. Despite appropriate therapy, wheezing may continue to be a problem during childhood and this is significantly correlated with the presence of a positive nasal smear at the time of initial allergy evaluation.