Mass General Study Finds a New Way to Use Poop Pills

Researchers may have identified a safer, more effective type of capsule.


Mass General photo by Samantha Carey

Poop pills are back, everybody.

Last month, we reported on an upcoming Massachusetts General Hospital study that’s trying to determine whether freeze-dried poop pills can help obese individuals lose weight by supplying them with the gut bacteria of thin, healthy donors. As it turns out, the fun doesn’t stop there.

Now, a new, separate study from the hospital says capsules containing fecal bacteria are also likely an effective treatment for C. Difficile infection (CDI), a bacterial condition commonly acquired in hospitals that can cause pain, diarrhea, and a potentially fatal hole in the bowel. CDI kills roughly 29,000 people in the U.S. each year.

While the two studies both focus on fecal capsules, they use them in different ways. The obesity study will use a process called fecal microbiota transplantation (FMT) to replenish good bacteria. The CDI study, on the other hand, used SER-109, which is undergoing testing for FDA approval. It uses bacterial spores from healthy human stool, but eliminates viruses, unnecessary bacteria, parasites, and fungi found in the sample. FMT has also been used to treat CDI in the past, with a good amount of success, but SER-109 looks to be a safer and better-regulated method.

“This oral microbial preparation that contains a small fraction of the total microbiome works as well as, if not better than, FMT,” senior author Elizabeth Hohmann said in a statement. “These few key species seem to work in restoring a healthy microbiome, and other, beneficial species not in the capsules return, while harmful bacteria are removed.”

The study looked at only 30 people, but almost 97 percent of them were cured of CDI symptoms by the end of the eight-week SER-109 regimen; all but four had no recurrences at all during that time period. The patients also saw their own good bacteria return after the trial ended. For comparison, an FMT regimen had 81 percent efficacy in a prior study.

All in all, it looks like fecal matter does, indeed, matter.