Adherence is the term currently used to describe a patient following prescribed or suggested treatment regimens. Jane Scullion looks at this concept in those with respiratory disease In respiratory diseases, there are good pharmacological and non-pharmacological therapeutic interventions that can improve symptoms, health status and quality of life for many, and in some cases transform and even save lives. What is not in place is a robust method for ensuring that the therapies and interventions that are prescribed or advised can and will be taken as instructed, and we call this nonadherence. This article looks at medicines adherence, using examples from respiratory diseases and their treatments, discussing what what is meant by it, the reasons it remains problematic, and what could be done about it in respiratory prescribing.