Understanding the principles of ethical clinical practice is fundamental to making appropriate decisions. While ethical practice is a regulatory and legal obligation, it more importantly improves clinical judgement and the delivery of effective care. Traditionally, there are four principles: autonomy (giving choice to the patient); beneficence (paternalism); nonmaleficence (do no harm); and justice (confidentiality and equality). However, a fifth principle, fidelity, which constitutes fairness, truthfulness and advocacy, must be included. Balancing between autonomy and beneficence is like walking on a tight-rope, particularly when dealing with children and young people. However, competence to make sensible autonomous decisions is not linearly related to age. Adults sometimes make bad decisions and do not necessarily understand the long-term consequences of their actions. Nevertheless, whereas children are not, adults are legally considered to have autonomous rights. Irrespective of age, generating an accord between clinician and patient through empathetic consultation has the best chance of achieving favourable patient experience and consequent optimal clinical outcomes. In most situations honesty and full disclosure should be the rule; but, very occasionally, it may be necessary to modify approaches to avoid adverse consequences. The five principles are discussed and illustrated with case scenarios. It is not always possible to achieve consensus and sometimes there are no correct answers to ethical dilemmas. But discussion with colleagues, ethicists, patients and their representatives will improve ethical clinical practice.