Corticosteroids are widely used in cancer care and acute oncology to manage symptoms of the patient’s condition and/or complications and side effects of anticancer treatment. When used correctly they can be effective, but they are themselves associated with a range of potential complications and side effects. Prescribing corticosteroids and caring for patients who are taking a corticosteroid course must therefore follow essential principles, so that the probability of benefits is increased and the risk of side effects is reduced. This article provides a comprehensive overview of the principles guiding the use of corticosteroids in cancer care and acute oncology. The author uses fictional case studies to demonstrate the effective and safe use of corticosteroids and outlines nursing interventions that will minimise the risk of complications and side effects, and therefore enhance patients’ quality of life.