SOMETIMES, BEYOND THE COUGH or rash that prompts a patient’s visit, a clinician comes face-to-face with other, larger forces: poverty, violence or a physically toxic environment that may be harming that patient. If doctors, nurses and other care providers have dedicated themselves to promoting health, where does that job begin, and where does it end—if indeed it ends at all? Should clinicians feel compelled to serve as advocates not just for their patients, but for a fairer, healthier world for them to live in?

In this issue, “Taking It to the Streets” (page 30) explores these questions. Last September, it was a pediatrician, Mona Hanna-Attisha, whose concern about the effects of Flint, Michigan’s lead-laced drinking water on the health of the city’s children helped draw worldwide attention to that crisis. She had learned to be an outspoken public advocate as a teenager and carried that sense of social responsibility into her work at Flint’s Hurley Medical Center, which supported and joined her efforts. Other clinician advocates, however, have been discouraged from raising their voices, underscoring the risks that prospective advocates may face.

The theme of clinician responsibility runs through this issue. We write about Nobel Prize–winning geneticist Hermann Joseph Muller, whose 1927 discovery of the connection between radiation and mutation led him to expose the perils of the nascent nuclear age. In an interview, Xóchitl Castañeda, who leads the Health Initiative of the Americas, argues for political reforms to improve care for undocumented immigrants. These noncitizens bear the brunt of the unpleasant, dangerous work in the nation’s fields and factories only to find a health system that is often stacked against them.

Here, in nearby Chelsea, MGH runs several programs that help immigrants and refugees. Responsibility for the community was our hospital’s founding tenet more than 200 years ago, and in 2013, when MGH assessed the health needs of Chelsea and two other neighboring communities, substance use was identified as the most pressing issue. Addressing the opioid epidemic and other aspects of that problem became a hospitalwide clinical priority. For this and other initiatives addressing the needs of underserved, vulnerable citizens, MGH recently received the 2015 Foster G. McGaw Prize for Excellence in Community Service, a prestigious national honor for organizations that significantly improve the health and well-being of the communities they serve.

Yet it’s one thing for a hospital to tackle such issues, and another for individual clinicians to step forward and take on societal issues that are often far more complex than any single disease. We salute them.