Lower airway obstruction can occur at the level of trachea, bronchi or bronchioles. It is characterized clinically by wheeze and hyperinflated chest, apart from other signs of respiratory distress. Common causes include bronchiolitis, asthma, pneumonia, laryngotracheo-bronchitis, congenital malformations and foreign body inhalation. Bronchiolitis usually occurs in children aged 2 months to 2 years. It is most commonly caused by respiratory syncytial virus infection. The diagnosis is mainly clinical, and investigations have a very limited role. Humidified oxygen and supportive therapy are the mainstays of treatment. A trial of inhaled epinephrine or parenteral steroids may be considered for non-responders. It is usually associated with good outcome.