His research focuses on gut microbiota in clinical disease states, particularly refractory C. difficile infection. He and Dr. Michael Sadowsky have established a UMN Microbiota Therapeutics Program within the BioTechnology Institute, which is now focused on developing human gut microbiota as a class of therapeutic agents. This group was the first to demonstrate prompt and sustained engraftment of entire microbial communities in patients with recurrent C. difficile infection and the first to develop a standardized protocol for production of human gut microbiota, which is now used in multiple clinical trials.