Fecal microbial transplants have been given to alter a recipient's metabolism to reduce obesity or alter immunity to fight cancer, and in those transplants recipients are not given suppressive antibiotics to eliminate the microbial community prior to the transplant. Researchers now report there is a lack of predictability for fecal microbial transplants to change the gut microbial community to correspond to that of the donor when there is no preconditioning to reduce the recipient microbe community. This contrasts with the C. difficile fecal microbial transplants after suppressive antibiotic therapy, where stable long-term colonization of donor strains is seen as long as two years post-transplant.