Acute viral bronchiolitis is the principal lower respiratory tract infection in infants worldwide, 10% of canadian infants are affected each year. It is characterized by a first episode of difficulty to breathe, preceded by symptoms of fever, rhinorrhea and cough. The only accepted treatment for bronchiolitis is nasal cleaning, hydration and oxygen administration. Multiple studies have documented variation in diagnostic testing, clinical scores used and different treatment modalities. This suggests a lack of consensus on the diagnosis, on criteria for hospitalization and on treatment. Nebulized 3% hypertonic saline solution has been proposed as a potential treatment for the reduction in the severity of respiratory symptoms and the rate of admission in bronchiolitis, it has never been studied alone and the effect on the rate of admission has been little studied.