Withholding or withdrawing a life-sustaining treatment tends to be very challenging for health care providers, patients, and their family members alike. When a patient's life seems to be nearing its end, it is generally felt that the morally best approach is to try a new intervention, continue all treatments, attempt an experimental course of action, in short, do something. In contrast to this common practice, the authors argue that in most instances, the morally safer route is actually to forgo life-sustaining treatments, particularly when their likelihood to effectuate a truly beneficial outcome has become small relative to the odds of harming the patient. The ethical analysis proceeds in three stages. First, the difference between neglectful omission and passive acquiescence is explained. Next, the two necessary conditions for any medical treatment, i.e., that it is medically indicated and that consent is obtained, are applied to life-sustaining interventions. Finally, the difference between withholding and withdrawing a life-sustaining treatment is discussed. In the second part of the paper the authors show how these theoretical-ethical considerations can guide clinical-ethical decision making. A case vignette is presented about a patient who cannot be weaned off the ventilator post-surgery. The ethical analysis of this case proceeds through three stages. First, it is shown that and why withdrawal of the ventilator in this case does not equate assistance in suicide or euthanasia. Next, the question is raised whether continued ventilation can be justified medically, or has become futile. Finally, the need for the health care team to obtain consent for the continuation of the ventilation is discussed.