Probiotics Evolve in the Gut (IMAGE) Washington University School of Medicine Caption Probiotics -- which are living bacteria taken to promote digestive health -- evolve once inside the body and have the potential to become less effective and sometimes even harmful, according to a new study from Washington University School of Medicine in St. Louis. The findings suggest that developers of probiotic-based therapeutics must consider how the probiotics might change after administration. Credit Mark Hallett Usage Restrictions This image is to be used in accordance with the mission, policies and guidelines of Washington University in St. Louis. Visit https://wustl.edu/about/compliance-policies/media-policies/photo-use/ for more information. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.