Imagine if in the 1960s surgeons like Christiaan Barnard or Norman Shumway had had to use the same rules that govern the development and testing of pharmaceutical medications when they were teaching the rest of the world how to transplant hearts from the recently deceased into their patients. The idea is absurd on the face of it. For starters, hearts do not come in standard sizes. Nor do all transplanted organs have the same "shelf life" the way different lots of properly manufactured drugs do.

So why does the U.S. Food and Drug Administration (FDA) regulate fecal transplants the same way that it does medications? That's the question that Mark B. Smith, Colleen Kelly and Eric Alm ask in the current issue of Nature (which is owned by the same company as Scientific American).

Fecal transplants have become increasingly important over the past few years as a way of basically taking the healthy gut bacteria out of one person and putting them in another person whose own gut bacteria are deficient in some way. (To learn more about this process and its benefits, check out Maryn McKenna's article "Swapping Germs" in the December 2011 issue of Scientific American)

Instead, Smith and colleagues argue that fecal transplants should be regulated by their own set of safety rules--in much the same way that organs and other tissue products (pig valves, corneas, cartilage, blood, etc.) are.

Currently, the FDA has given fecal transplants a kind of waiver from some of the stricter rules that govern the development and testing of medications. But that's only as long as the treatment is used strictly for C. difficile infections, which cause debilitating gastrointestinal problems and are not otherwise easily curable. Many physicians and patients would like to know if the therapy could be made to work for other bowel problems--such as Crohn's disease.

But the stricter FDA rules would make it harder to test fecal transplants for no good reason. Regulating fecal transplants like other tissue products would still keep patients safe, the authors argue. And it would undoubtedly keep the cost of treatment lower than would otherwise be possible if some large company with deep pockets had to undertake the sorts of tests that would need to be done to approve fecal transplants as if they were drugs. After all, if there's something we have a lot of in this world, it's poop.