Ketamine is an N-methyl-D- aspartate antagonist with rapid antidepressant effects. Research shows that ketamine has a fast onset of reduction in depressive symptoms and shows sustained remission of suicidal ideation in some patients. This article provides a brief review of the literature on the use of ketamine for depression and in acute cases of suicidality. The authors conclude that, while further investigation is needed, ketamine may be a useful treatment option for acute suicidality in emergency room settings.