Although not as well-known as other medical conditions, sepsis kills more people in the United States than AIDS, breast cancer, or prostate cancer combined. Sepsis is body-wide inflammation, usually triggered by an overwhelming immune response to infection. Though doctors and medical staff are well-aware of the condition—it is involved in 1 in 10 hospital deaths—the condition is notoriously hard to diagnose. In this video, sepsis expert Sarah Dunsmore, a program director with the National Institute of General Medical Sciences (NIGMS), describes what sepsis is and how to recognize it, what kinds of patients are most at risk, and what NIGMS is doing to reduce the impact of this deadly condition.