Upstreamists like me — and we can be doctors, nurses or other clinicians — know that asthma can start in the air around us. We know that ailments such as depression, anxiety and high blood pressure can arise from chronically stressful conditions at work and home. We see how policies that deny opportunity, fairness and justice can be reflected in patients’ faces as well as in their DNA. And, just as important, we understand how to translate this knowledge into action. The upstreamist considers it her professional duty not only to prescribe a chemical remedy but also to tackle sickness at its source.