If you have asthma, your doctor may prescribe a nebulizer as treatment, or breathing therapy. The device delivers the same types of medication as metered-dose inhalers (MDIs), which are the familiar pocket-sized inhalers, but works differently. Nebulizers may be easier to use than MDIs, especially for children who aren’t old enough to properly use inhalers, or adults with severe asthma.

A nebulizer turns liquid medicine into a mist to help treat your asthma. They come in electric or battery-run versions. They also come in a larger size that’s meant to sit on a table and plug into a wall, and a smaller size you can carry with you. Both are made up of a base that holds an air compressor, a small container for liquid medicine, and a tube that connects the air compressor to the medicine container. Above the medicine container is a mouthpiece or mask you use to inhale the mist.

Pressurized air passes through the tube and turns the liquid medicine into a mist. During an asthma attack or an infection, the mist may be easier to inhale than the spray from a pocket inhaler. When your airways become narrow — like during an asthma attack — you can’t take deep breaths. For this reason, a nebulizer is a more effective way to deliver the medication than an inhaler, which requires you to take a deep breath.

Nebulizers can deliver short-acting or long-acting asthma medication. Also, more than one medication can be given in the same treatment. The type of medication and dose will be prescribed by your doctor. You may receive premixed containers of liquid that can be opened and placed in the machine, or you may have to mix the solution before each use.