In medicine, a nebulizer(spelled nebuliser in British English) is a device used to administer medication in the form of a mist inhaled into the lungs.

Nebulizers are commonly used for treatment of cystic fibrosis, asthma, COPD and other respiratory diseases.

Nebulizers use oxygen, compressed air or ultrasonic power to break up medical solutions and suspensions into small aerosol droplets that can be directly inhaled from the mouthpiece of the device. The definition of an aerosol is a “mixture of gas and liquid particles,” and the best example of a naturally-occurring aerosol is mist, formed when small vaporized water particles mixed with hot ambient air are cooled down and condense into a fine cloud of visible airborne water droplets. When using a nebulizer for inhalation therapy with medication to be administered directly to the lungs, it is important to note that inhaled aerosol droplets can only penetrate into the narrow branches of the lower airways if they have a small diameter of 1–5 micrometers. Otherwise they are only absorbed by the mouth cavity, where the effect is low.

A nebulizer changes medication from a liquid to a mist so that it can be more easily inhaled into the lungs. Nebulizers are particularly effective in delivering asthma medications to infants and small children and to anyone who has difficulty using an asthma inhaler.

It is also convenient when a large dose of an inhaled medication is needed. Nebulized therapy is often called a “breathing treatment.” And a variety of medications — both for immediate relief and maintenance of asthma symptoms — are available for use with a nebulizer.

Nebulizers come in home (tabletop) and portable models. Home nebulizers are larger and must be plugged into an electrical outlet. Portable nebulizers run on batteries — either disposable or rechargeable — or can be plugged into a car’s cigarette lighter. Smaller, portable units are slightly larger than a deck of cards, so they can be carried in a purse, briefcase, or backpack to be used whenever and wherever you need them.

To obtain a nebulizer, you need a prescription from your doctor. Home nebulizers vary in cost, ranging from about $50 and up, plus the cost of accessories.

Portable nebulizers usually cost a little more than home nebulizers. Both are usually covered under the durable medical equipment portion of health insurance policies. But, most insurance companies will require you to work with a specified durable medical equipment supplier. Check with your insurance company before purchasing or renting to ensure it will be covered. Your health care provider should be able to assist you with these arrangements.