Bronchodilators are medicines that relax (dilate) the airways of the lungs (bronchial tubes). This makes it easier for a person to breathe in more air.

Bronchodilators are usually given through an inhaler, which makes a fine mist that the person breathes through the mouth and into his or her lungs. Inhaled bronchodilators are preferred for treating respiratory problems, such as asthma. They cause few side effects and are effective.

Bronchodilators are sometimes given in pill form or as an injection under the skin for a person who cannot use an inhaler.