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You Won’t Believe What’s In These Pills

Posted on by Dr. Francis Collins

Fecal pills
Credit:: Hohmann lab

Clostridium difficile, or more commonly “C. diff,” is a nasty bacterium that claims the lives of 14,000 Americans every year. Most at risk are people with conditions requiring prolonged use of antibiotics, which have the unfortunate side effect of wiping out the natural, good bacteria in the colon—thus allowing bad bugs like C. diff to multiply unchecked. In many folks, C. diff infection can be treated by halting the original antibiotics and switching to other types of antibiotics. But for some people, that doesn’t work—C. diff is either resistant to treatment or makes a hasty comeback.

What’s to be done then? Well, researchers have known for some time that taking microbe-rich stool samples from healthy people and transplanting them into C. diff patients helps to improve their symptoms. The challenge has been figuring out a safe and effective way to do this that is acceptable to patients and doesn’t involve invasive procedures, such as colonoscopy or nasogastric tubes [1,2]. Could there be a simple solution? To put it more bluntly: what about poop pills?

A team of NIH-funded researchers at Massachusetts General Hospital in Boston have now successfully tested that very strategy: they purified healthy stool samples in a way that concentrated the good bacteria, placed the resulting material into capsules, and then froze the capsules. The researchers led by Ilan Youngster and Elizabeth Hohmann, both infectious disease specialists, tested these frozen poop pills on 20 volunteers who had experienced at least three C. diff infections and failed to respond to a six-to-eight week course of the antibiotic vancomycin—the usual treatment for ridding the body of this microbe.

In a study published in the journal JAMA [3], the patients, who ranged in age from 11 to 89, received 30 pills over two days. After the initial course of treatment, 14 of the 20 patients felt better and their frequent bouts of diarrhea ceased, with no recurrence after eight weeks. The remaining six patients, who were sicker when the trial began and didn’t respond to the first round of pills, were given a second treatment one week later. The additional treatment proved successful in four. Altogether, these pills successfully treated C. diff in 90% of patients.

That’s great news, but you may still have qualms about any medicine made of poop. Well, the odorless frozen capsules must not have been too revolting because researchers said all of the patients completed one round and some even two rounds of treatment without any unpleasant consequences. In fact, one patient even reported that swallowing the capsules was rather like swallowing small ice chips.

Researchers say that someday it may be possible to grow these beneficial bacteria in the lab rather than harvest them from stool samples. In the meantime, larger, controlled studies are needed to confirm that the current generation of poop pills really work to knock out C. diff infections. If so, this innovative therapeutic approach may have potential for treating a range of other gastrointestinal problems in which the microbiome is out of whack.


[1] Fecal microbiota transplant for relapsing Clostridium difficile infection using a frozen inoculum from unrelated donors: a randomized, open-label, controlled pilot study. Youngster I, Sauk J, Pindar C, Wilson RG, Kaplan JL, Smith MB, Alm EJ, Gevers D, Russell GH, Hohmann EL. Clin Infect Dis. 2014 Jun;58(11):1515-22.

[2] Duodenal infusion of donor feces for recurrent Clostridium difficile. van Nood E, Vrieze A, Nieuwdorp M, Fuentes S, Zoetendal EG, de Vos WM, Visser CE, Kuijper EJ, Bartelsman JF, Tijssen JG, Speelman P, Dijkgraaf MG, Keller JJ. N Engl J Med. 2013 Jan 31;368(5):407-15.

[3]  Oral, capsulized, frozen fecal microbiota transplantation for relapsing Clostridium difficile infection. Youngster I, Russell GH, Pindar C, Ziv-Baran T, Sauk J, Hohmann EL. JAMA. 2014 Oct 11. [Epub ahead of print]


Clostridium Difficile Infections, National Library of Medicine, NIH

Ilan Youngster, The Harvard Clinical and Translational Science Center

Elizabeth L. Hohmann, The Harvard Clinical and Translational Science Center

NIH Support: National Center for Advancing Translational Sciences

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