For the new study, his team extracted healthy gut bacteria from donated stool. Then they froze the microbes into capsules. This greatly prolongs the “shelf life” of the microbes. The researchers gave the capsules to 20 people with C. diff infections. In 14 patients, the infections cleared up after taking a two-day regimen, or 30 capsules. Four more people improved after a second round of capsules. The overall success rate for the treatment was 90 percent, the researchers reported October 11 in the Journal of the American Medical Association.