Any mentally competent adult has the right to give or refuse consent to treatment or nursing intervention. The ethical principle underpinning this free choice is respect for autonomy, and the nurse's professional duty to respect the decision of the patient is enshrined within the NMC's Code of Conduct (NMC, 2008). Capacity is paramount to consent and problems arise in practice when the patient is deemed to lack capacity. In this instance, the provisions of the code of practice of the Mental Capacity Act apply (2005). The aim of this article is to present the issues that arise when patients lack decision-making capacity, especially in relation to older adults with dementia who lack the capacity to consent to medication, as well as the covert administration of medication. In relation to consent and covert administration, the nurse is required to balance respect for the patient's autonomy with their desire to act beneficently and in a non-maleficent manner and emphasis will be given to these underlying ethical principles throughout the article.