The clinical status of terminal cancer patients is very complex and is affected by several severe symptoms, of extended duration, changing with time and of multifactorial origin. When there are no reasonable cancer treatments specifically able to modify the natural history of the disease, symptom control acquires priority and favours the possible better adaptation to the general inexorable deterioration related to the neoplasic progression. Despite the important advances in Palliative Medicine, symptoms are frequently observed that are intolerable for the patient and which do not respond to usual palliative measures. This situation, characterised by rapid deterioration of the patient, very often heralds, implicitly or explicitly, approaching death. The intolerable nature and being refractory to treatment indicates to the health-care team, on many occasions, the need for sedation of the patient. The requirement for sedation of the cancer patient is a situation that does not allow for an attitude of doubt regarding maintenance of the patient in unnecessary suffering for more than a reasonable time. Given the undoubted clinical difficulty in its indication, it is important to have explored at an earlier stage all usual treatments possible and the grade of response, commensurate with the patient's values and desires. Sedation consists of the deliberate administration of drugs in minimum doses and combinations required not only to reduce the consciousness of the patients but also to achieve adequate alleviation of one or more refractory symptoms, and with the prior consent given by the patient explicitly, or implicitly or delegated. Sedation is accepted as ethically warranted when considering the imperative of palliation and its administration and, whenever contemplated, the arguments that justify them are clear recorded in the clinical history. It is not an easy decision for the physician since, traditionally, the training has been "for the fight to save life". Nevertheless, it seems necessary to make some preparations regarding these problems that have a central affect on the clinical oncologist in his daily function.