Clinical criteria used to define acute broncholitis in infants are not worldwide consensual diagnostic criteria. Respiratory failures as well as young age account for the severity of the disease. Laboratory analyses are useless in community medical practice. Infectious complications are due to secondary infection with usual respiratory pathogenic bacteria. In France the treatment mainly consists in physical therapy whose efficiency is currently being evaluated by randomized studies. Prevention of the disease relies on hygiene measures and in an integrated physician-physiotherapist collaboration.