The phrase ‘informed consent’ is used widely in healthcare. Practitioners ask their patients for their consent to a treatment or a diagnostic or monitoring procedure and, if consent is given, will document this. There is a general understanding that consent is a prerequisite for care and signifies the patient’s permission for the paramedic to proceed with assessments and other therapeutic interventions. Obtaining the patient’s informed consent is fundamental to contemporary healthcare: what is informed consent and why is it so important? This article explores the meaning of consent in practice and the purpose it serves. It will then go on to consider complex circumstances, including emergencies, young people aged under 18 years, when a patient is unable to give consent or where a person has capacity to consent but refuses.