Bronchiolitis is an infection of the bronchiolar epithelium. It is associated with profound submucosal and adventitial edema, increased secretion of mucus, and obstructed flow in the small airways, leading to hyperinflation, atelectasis, and wheezing. Respiratory syncytial virus (RSV) is responsible for the majority of cases .Bronchiolitis is the most frequent lower respiratory tract infection with high morbidity, and the leading cause of hospitalization in young children. Studies from developed countries report an incidence hospitalization of 30 per 1000 children in the first year of life and an annual mortality rate of 1.82-2 per 100,000 live births. The cost of treatment is about $2.5 billion yearly. One group from the United States estimated the annual hospital costs for bronchiolitis at $365-$691 million.