Chronic wounds that won’t heal are a common complication of diabetes. Because scientists don’t understand the reasons for the healing problems, few treatment options are available. Previous work with mouse models of diabetic wounds suggests that elevated levels of two matrix metalloproteinase enzymes—MMP-8 and MMP-9—might play a role. Because MMP-8 is also found in nondiabetic wounds, scientists think it has a beneficial effect. Levels of MMP-9, in contrast, are elevated only in diabetic wounds, suggesting it might contribute to the inability of those wounds to heal. Mayland Chang and coworkers at the University of Notre Dame targeted those two MMPs with a combination therapy that accelerates healing in a diabetic-wound mouse model (Proc. Natl. Acad. Sci. USA 2015, DOI: 10.1073/pnas.1517847112). The researchers topically applied active MMP-8 and a small-molecule inhibitor of MMP-9 known as ND-336 to mice. The combination decreases inflammation, enhances formation of new blood vessels, which are needed for healing, and speeds healing more than either treatment alone.