As a general rule, any medical action should be proportionated. That is, the expected benefit of the treatment provided must be commensurate to the diagnosis and prognosis, the therapeutic efforts the suffering caused to the patient, and the eventual risks. Inversely a disproportionate or excessive medical action that will result in no benefit to the patient is technically incorrect and ethically reprehensible. As opposed to ordinary methods of treatment (basic nursing, feeding, hydration, drugs and regular clinical procedures), we reserve the name of "extraordinary methods of treatment" to those medical actions using complex and invasive high-cost procedures and equipment that should be urgently indicated in any critically ill patient with a potentially reversible disease. These do not have any indication in terminally ill patients, except in the case of concomitant potentially reversible acute complications. When a DNR (do not resuscitate) order is adopted it should be reassessed periodically. The use, withholding and withdrawal of these extraordinary measures of treatment are subject to a series of medical and ethical requirements, which receive full discussion in this paper (Rev Méd Chile 2003; 131: 685-92)