Policymakers are increasingly concerned that a relatively new class of anti-depressant drugs, selective serotonin re-uptake inhibitors (SSRI), may increase the risk of suicide for at least some patients, particularly children. Prior randomized trials are not informative on this question because of small sample sizes and other limitations. Using variation across countries over time in SSRI sales and suicide, we find that an increase of one pill per capita (a 13 percent increase over 1999 levels) is associated with a 2.5 percent reduction in suicide rates, a relationship that is more pronounced for adults than for children. Our findings suggest that expanding access to SSRIs for adults may be a cost-effective way to save lives, although policymakers are right to remain cautious about pediatric use of SSRIs.