This information is for parents of a baby or young child with wheezing. It tells you about quick-relief inhalers, a treatment used for wheezing in babies and young children. It is based on the best and most up-to-date research.
Do they work?
Yes. Some research shows that when young children are having an attack of wheezing, a quick-relief inhaler can help to improve their symptoms.
Young children often find using a spacer device or a nebuliser easier to use than an inhaler.
What are they?
Children with asthma have airways that are extra-sensitive to substances called asthma triggers. When they breathe in an asthma trigger, the muscles around the walls of the airways tighten, and the passageways become narrower, making it difficult for air to get through.
Quick-relief inhalers help relax the muscles in the lungs so that the airways open up, making it easier for children to breathe.
Your doctor may call these medicines bronchodilators, because they dilate (open up) the bronchial tubes (airways).
Asthma medicine is often delivered through an inhaler. Inhalers that relieve wheezing quickly are usually blue.
The two inhalers that have been studied in babies and young children contain one of these drugs:
Breathing in one of these drugs is a good way to make sure it gets straight to the lungs, which is where it is needed. Young children are usually given these medicines through a spacer device attached to an inhaler, or through a nebuliser. That's because it can be hard for them to use the same inhalers as older children. It can take quite a bit of coordination to press down on an inhaler and breathe in at the same time. To read more, see How to take asthma drugs.
How can they help?
Inhaling the drug salbutamol may: 
Reduce your child's wheezing
Help your child breathe more easily and make him or her more comfortable
Slow down your child's breathing (breathing speeds up during an asthma attack so more air gets into the blocked airways).
But using salbutamol won't help to keep your child out of hospital. A child who takes salbutamol is just as likely to be admitted to hospital with asthma as a child who takes a dummy treatment (a placebo).  
Some studies have looked at the best way to give young children medicine that relieves asthma symptoms quickly.    They showed that using a spacer device with a mask attached works as quickly as using a nebuliser. But how children take their asthma drugs does not change how likely it is that they will go to hospital because of their asthma.