"Sounds Gross, Works Great: Fecal Transplants Cure Nasty C. Diff Infections"

Given the predelictions of the medical profession, it's only used as a last resort:

"A new review of more than two dozen scientific reports involving 317 patients, some dating back 50 years, finds that fecal bacteriotherapy, commonly known as fecal transplant, cured the problem in 92 percent of the cases. Nearly all got better after just one treatment. That's a better record than other treatments, including probiotics, toxin-binding molecules and an experimental vaccine."

The bacteria from the healthy donor out-compete the bad bugs, and you get better without using antibiotics to destroy your symbiotic biome. 

Which is what causes C. Diff infections in the first place.