Stool transplants are exactly what they sound like: moving poop from a healthy person into a sick person, perhaps via a pill or an enema. I bring this up because most people cringe at the idea - but they're a treatment proven effective for some antibiotic-resistant infections caused by the Clostridium difficile, or C. diff bacteria, which kill tens of thousands of people per year. A common sweetener may be worsening these C. diff infections.