Nature interviews Lawrence Brandt, M.D., about the first randomized clinical trial on using fecal transplants to treat recurring infections of Clostridium difficile, a bacterium that causes severe diarrhea. While the standard antibiotic treatment cured 27% of patients in the trial, fecal transplants cured 94%. Dr. Brandt currently leads a blinded trial in which patients are treated with their own feces or those from healthy donors. Dr. Brandt is professor of medicine and of surgery at Einstein and emeritus chief of gastroenterology at Montefiore Medical Center.