Although bronchiolitis is the most common viral lower respiratory tract infection in infancy and childhood, and the virus responsible (respiratory syncytial virus) was discovered half a century ago, there is no effective treatment available. The antiviral agent ribavirin has not lived up to expectations and should be reserved for selected cases. Corticosteroids have not been shown to be effective in individual trials, although a recent meta-analysis suggested a mild beneficial short-term effect. Bronchodilators can be used on a trial-and-error basis. Prophylaxis with intravenous immunoglobulins enriched for anti-respiratory syncytial virus antibodies or humanized monoclonal antibodies can reduce the rates of related hospitalization by 50% when used in high-risk patients. However, logistical problems with the administration of intravenous immunoglobulins and the cost of both products preclude their widespread use.