The country’s first stool bank, OpenBiome, is now selling capsules of fecal matter to treat life-threatening Clostridium difficile, or C. diff, infections.

The $635 pill-based therapy, a type of fecal transplant, is highly effective against the difficult-to-treat gastrointestinal infection, according to results of a pilot study. A single dose, which includes a whopping 30 pills, cured 70 percent of patients. A second dose bumped the success rate up to 94 percent. The treatment, currently being sold only to doctors, may offer an easier alternative to other effective fecal transplant routes, namely colonoscopies, nasal tubes, and enemas.

Scientists have known for years that fecal transplants in general are highly effective against C. diff infections, which can be extremely difficult to cure. The infection can cause severe, recurring diarrhea. It can be resistant to antibiotic treatments, and sometimes it turns deadly. In the US, C. diff causes more than 450,000 infections a year, leading to about 15,000 deaths.

C. diff infections sometimes take root while a patient is on antibiotics, which kills off and disrupts the patient's normal, healthy gut microbiome. In antibiotics’ wake, C. diff bacteria that usually reside quietly in the gut can run amok and produce toxins. Fecal transplants can stamp out the infection by replacing a patient’s disrupted gut microbial community with the gut microbes from a healthy patient, transferred via feces.

Besides pills, researchers and doctors have used a variety of methods to transplant fecal matter into the intestines of patients. And some researchers are also working on poop-less microbe mixes that could be taken in pill form.

Despite years of preliminary studies showing that fecal transplants can be safe and effective, experts are still struggling to monitor and standardize methods for administering prescription poop. The Food and Drug Administration, which oversees fecal transplants, has not approved the new OpenBiome capsules. As the New York Times reports, the agency has decided not to take action for now due to a current lack of alternatives.