An asthma inhaler is a canister that contains asthma medication. The medication is delivered through a plastic mouthpiece when the asthma patient presses a button. Some asthma containers have counters that show how many doses are left in the canister.

There are two types of asthma inhalers. The metered dose inhalers have a propellant that shoots the medication through the plastic mouthpiece. Some people find metered dose inhalers difficult to use since it requires some finger-lung coordination. When the person presses the button, they must be inhaling the medication immediately. This is difficult for some people, especially children. Spacers can be used to give the child more time to inhale the medication. A spacer is a plastic chamber that fits onto the mouthpiece of the inhaler. The medication will briefly hang in the air of the chamber as the child inhales it.

Dry powder inhalers do not have propellants. When people use dry powder inhalers, they must swiftly inhale the medication. Some asthma patients find dry powder inhalers difficult to use since the patient must forcefully and quickly inhale the asthma medication. This can be especially difficult during an asthma attack. Spacers cannot be used with dry powder inhalers.

An asthma inhaler counter lets asthma patients and parents of children with asthma know how many doses of asthma medication remain in the inhaler. Some asthma counters have a color system to indicate how much medication remains. Other asthma inhaler counters show the number of remaining doses. Without an asthma inhaler counter, people have had to guess how much medication remained. The asthma inhaler counter allows people to plan their prescription refills to ensure they always have adequate doses of asthma medication.

Without the counter, people are left to guess how much medication remains in the inhaler or keep a record of their doses. Some people with asthma resort to floating the canister in water to see how empty it is. The more it floats, the emptier it is. People may misjudge the amount of medication since other liquids may be present in the inhaler long after the medication runs out. Therefore, spraying the inhaler and attempting to see or taste for medication can be misleading.

Several different asthma inhalers now come with inhaler counters. In 2007, GlaxoSmithKline announced that its corticosteroid asthma medication known as Flovent was available with asthma inhaler counters for both the dry powder and metered dose inhalers.