Researchers have succeeded in targeting and killing E. coli without causing harm to the surrounding community of commensal bacteria in a simulated small intestinal microbiome using a cocktail of viruses (bacteriophages). The study proved that this approach is as effective as using broad-spectrum antibiotics. The experiment underlines the potential of using bacteriophages for target-specific manipulation of complex microbial communities and potentially replacing or supplementing usage of antibiotics against bacterial diseases.