Inhaled therapies are the mainstay of delivering medicines for people with respiratory diseases such as asthma. When compared with systemic administration, if used correctly, inhalers deliver a smaller amount of the drug directly to the site of action in the lungs, with a faster onset of effect and with reduced systemic availability, which minimises adverse effects. Despite this being the preferred method of efficient delivery of medication to the lungs, evidence suggests that many people are unable to use their inhalers effectively.