I nflammation-associated lung injury is a major cause of morbidity and mortality for patients in intensive care units. Although the cellular and molecular events that initiate lung inflammation are now well understood, the mechanisms that promote its resolution remain poorly defined. In this issue of the JCI, D’Alessio et al. show in a mouse model that recovery from acute lung injury is not simply a passive process, but involves Tregs in an active resolution program (see the related article beginning on page 2898).