AIM: This article presents a discussion of the use of palliative sedation in response to intractable (not responsive to treatment) existential suffering. BACKGROUND: Patients suffering from a terminal illness are often faced with severe symptoms at the end of life. Although palliative sedation is sometimes used when no other options are effective in relieving unbearable pain or suffering, its use in response to intractable existential suffering in terminal illness remains controversial. DATA SOURCES: A literature search was conducted for published articles addressing the use of palliative sedation between 1996 and 2009 using established databases. DISCUSSION: Palliative sedation remains an uneasy practice. The debates have centred on ethical issues surrounding decisions to use sedation and on separating the intent of palliative sedation (relief of intolerable symptoms) from the intent of euthanasia (hastening death). There is lack of consensus in defining existential suffering. Consequently, there is limited understanding of how decisions are being made when using palliative sedation to treat intractable existential suffering. CONCLUSIONS: Given the confusion and uncertainty about ethical and clinical justifications for palliative sedation in treating existential suffering, we argue that a better understanding of the controversies and decision-making process is needed. Greater understanding is required to prevent palliative sedation from becoming a substitute for intensive treatment of this kind of suffering.