Introducing forest soil on an entryway doormat shifted the indoor microbiome of Finnish homes closer to bacterial profiles found outdoors, with less contribution from human-associated bacteria, a new study shows. In the future, such interventions rebalancing the home microbiome could be used for health promotion, especially in urban settings. The study was led by the Finnish Institute for Health and Welfare and the University of Eastern Finland and is published in the journal Microbiome.