In a frank and public act of self-examination, a group of doctors at Massachusetts General Hospital published an article Wednesday in the New England Journal of Medicine detailing the missteps that led to the death of a cancer patient who received a fecal transplant as part of an experimental trial. The man who died, and another who became severely ill, had received fecal matter from a donor whose stool turned out to contain a type of E. coli bacteria that was resistant to multiple antibiotics.

The death shook the emerging field of fecal microbiota transplants, or F.M.T., a revolutionary procedure that transfers feces from healthy donors to the bowels of sick patients in an effort to restore their microbiome, the community of beneficial bacteria and other organisms that dwell in the intestines.

Fecal microbiota transplants remain unapproved by the Food and Drug Administration, but the treatment has proved highly effective in combating a deadly bacterial infection known as Clostridium difficile, which kills thousands of Americans annually. Researchers have also been exploring its use for conditions ranging from Alzheimers to autism.

Dr. Elizabeth L. Hohmann, the lead author of the article and an infectious disease specialist who oversees fecal transplant trials at Mass General, expressed remorse over her lab’s failure to test stool from a donor that had been stored in a freezer for several months.