Asthma inhaler. This is a pump which dispenses a bronchodilator drug to relieve the symptoms of asthma. Asthma causes breathing difficulties due to contraction of the airways in the lungs. The drug widens these airways, allowing rapid relief from wheezing and breathlessness. This inhaler does not use CFCs (chlorofluorocarbons) as the propellant for the drug. CFCs damage the protective ozone layer above the Earth.