Turns out, the childhood rhyme is true: Dirt don’t hurt—and it might even help. A 2016 study led by neuroscientist Christopher Lowry at the University of Colorado Boulder suggests that exposure to Mycobacterium vaccae, a type of bacterium that lives in the soil, may have a positive effect on mental health. Why? Chronic inflammation is a risk factor for a host of psychiatric disorders, and some microbes found in rural environments are known to act as anti-inflammatories and immunoregulators. Indeed, scientists found that mice immunized with Mycobacterium vaccae are more resilient in the face of stress. Translation: Playing in the dirt—enough that you expose your immune system to soil bacterium—could lessen your anxiety. Dig in.