https://www.quora.com/What-is-poop-transplant
Andrew Freinkel, former neurologist and psychiatrist at Stanford University Medical Center
Sometimes, the colon becomes overrun with VERY harmful bacteria which almost overwhelms the immune system. In this procedure, enemas are given to flush the those bacteria. Then, “good” bacteria are put into the colon — tranplanting the bacteria— creating a colony in the gut which is healthy. People who were really sick with colitis become, almost miraculously, better.