Palliative sedation (PS), the medical act of decreasing a patient's awareness to relieve otherwise intractable suffering, is considered by some commentators to be controversial because of its consequences on residual survival and/or quality of life, and to be inappropriate for treating pure existential suffering. We will argue that PS must be always proportional, i.e. controlling refractory symptoms while keeping the loss of personal values (communication, affective relationships, care relationship) as low as possible, and that imminence of death is necessary too, from an ethical point of view, if a deep and continuous sedation (DCS) is proposed. Moreover, in case of pure existential suffering DCS should only be considered after repeated trials of respite sedation. The use of progressive consent and advance care planning to share the decision with the patient and to involve the family in the decision process as much as the patient desires is another ethical aspect to be pursued. Producing, implementing and sustaining guidelines at the higher scientific and professional level promise to help in improving both clinical and ethical aspects of the practice of PS.