Ever since the FDA stopped making doctors seek approval to perform fecal transplants on Clostridium difficile patients (C. difficile) in early 2013, the procedure has become more widely accepted. The method, which involves introducing fecal matter from a healthy donor into the gut of an unhealthy donor, has a 90 percent success rate, so its increasing popularity should come as no surprise. Perhaps more surprising is that, until now, few researchers have tried to freeze donated stool to see if it works as well as the fresh kind. Fortunately, a group of researchers at the Massachusetts General Hospital have given it the old clinical study try. And — lo and behold — frozen poo works, too.