To provide relief from specific symptoms, for example pain, and managing side effects as well as therapeutic purposes.

As part of the process of diagnosing their illness, to prevent an illness, disease or side effect, to offer relief from symptoms or to treat a disease

As part of the treatment of long term diseases, for example heart failure, and the prevention of diseases such as asthma.

To treat acute illness, for example antibiotic therapy for a chest infection, and side effects such as nausea.