Investigators have identified a non-antibiotic drug active against Clostridium difficile virulence factors, according to a new study published in Science Translational Medicine. Targeted screening of compounds for inhibitory activity against the cysteine protease domain within the C. difficile major virulence factor toxin B, identified a bioactive compound currently in human clinical trials for an unrelated indication. In a mouse model of C. difficile infection, the drug reduced disease pathology and inhibited release of the toxic glucosyltransferase domain.