Covert administration of medicines is a complex issue and involves disguising the administration of a medicine (e.g. in food or drink) to a patient lacking the capacity to consent to treatment. This Medicines Q&A discusses some of the legal issues that need to be considered before medicines are given covertly. It also addresses some of the pharmaceutical issues (e.g. absorption, incompatibility, interactions) and patient factors (e.g. acceptability) that need to be considered when deciding whether to administer medicines in this way.