A case report published Feb. 4 in the journal Open Forum Infectious Diseases details how a normal-weight female patient suffering from a C. difficile infection “rapidly became obese after receiving a fecal transplant from an overweight relative.” The patient, now cured, has “gained more than 40 pounds since the transplant” and is still putting on weight. The authors of the case report wrote, “This case serves as a note of caution when considering the use of non-ideal donors for fecal microbiota transplant (FMT), and we recommend selecting non-overweight donors,” a conclusion echoed by the authors of an accompanying editorial.