Conventional wisdom says it takes 15 years for a medical therapy, once proven safe and effective, to be widely accepted by the medical profession.

In the case of one particular treatment, however, a growing cadre of doctors and patients turned conventional wisdom on its head, enthusiastically adopting a procedure before the evidence was in — so enthusiastically, in fact, that the Food and Drug Administration was recently forced to rescind its restrictions.

The treatment, now widely employed against recurrent attacks by a nasty intestinal bug known as Clostridium difficile and tested on Crohn's disease and colitis, is one you'll likely never see advertised on TV: the fecal microbiota transplant, politely known as the FMT.

Acronym or no, a rose is a rose is a rose, and a poop transplant, likewise. Born of desperation on the part of patients and their doctors, an infusion of fecal material from a healthy donor has risen from folk wisdom to near-mythical status. Despite a "yuk" factor, an increasing number of patients have undergone the procedure in top hospitals, clinics and even in their homes, doctors say.

In a first-of-its-kind research study just concluded at Seattle Children's, the treatment significantly helped kids with Crohn's.

So far, the transplant's biggest success has been against the bug commonly known as C. diff, which now strikes upward of half a million people a year in the United States. With the emergence of a particularly virulent strain, it has been deemed a "global public health challenge" by the Centers for Disease Control and Prevention.

The infection can cause relentless diarrhea, a potentially life-threatening complication, particularly for older people. This notorious bacterium typically proliferates when a person's natural intestinal bacteria — which normally outnumber and marginalize such bad actors — are laid low, most often by antibiotics.

In theory, FMT repopulates the compromised intestine with a healthy mix of fecal bacteria that kicks the bad bugs' butts. But until recently, with scant first-rate research, doctors intent on helping their patients had to rely mostly on anecdotal evidence.

"I became one of those desperate doctors," said Dr. Christina Surawicz, a gastroenterologist in Seattle who first used the treatment in 2004. No conventional medications were working for her patient, who had been miserable for nine months. "I took a leap of faith."

The transplant, taken from the patient's husband and given via colonoscopy, worked. Surawicz, long a researcher of C. diff, wasn't the first locally to do such a transplant, but became known as a pioneer. Around the nation, a small underground of gastroenterologists and infectious disease specialists began experimenting with the procedure, making up protocols as they went.

There was indeed a "yuk" factor. "Most people would say, 'You're going to do whaaaat?'?" recalled Dr. Francis Riedo, an infectious-disease specialist at EvergreenHealth in Kirkland, Wash. "But by the time we saw those patients, they were so miserable, so desperate, they would try anything."