You read that right! Fecal transplantation involves taking one person’s poop and implanting it into another person via enema, colonoscopy, or nose tube, thereby giving the second person a trove of helpful new gut bacteria and chemicals. There have been cases of patients with fatal C. diff infections who took a pill of fecal bacteria donated by healthy family members were cured of the disease. And in a recent study, mice that were implanted with the poop of obese humans got fat, while those who got skinny people’s poop did not.

MORE: The Promise of Fecal Transplants