This paper reviews quantitative evaluations of the efficacy of intervention programs designed to reduce the pain and suffering associated with bereavement. After identifying the psychological and physical health impacts of bereavement and outlining the prevalence of detrimental outcomes, we conclude that a minority of bereaved persons experience severe and sometimes lasting consequences, whereas the majority manage to overcome their grief across the course of time. We detail criteria for establishing the efficacy of bereavement intervention and examine the impact of intervention according to these stringent criteria. We critically examine previous reviews and summarize their conclusions. Using a narrative review approach, we apply a public health framework to organize intervention programs into primary, secondary, and tertiary prevention strategies. A comprehensive, updated review of empirical studies in these categories leads to the following conclusions: Routine intervention for bereavement has not received support from quantitative evaluations of its effectiveness and is therefore not empirically based. Outreach strategies are not advised, and even provision of intervention for those who believe that they need it and who request it should be carefully evaluated. Intervention soon after bereavement may interfere with "natural" grieving processes. Intervention is more effective for those with more complicated forms of grief. Finally, a research agenda is outlined that includes the use of rigorous design and methodological principles in both intervention programs themselves and in studies evaluating their efficacy; systematic investigation of "risk factors"; and comparison of relative effectiveness of different intervention programs (i.e., what works for whom).