 Interrupted by irritable bowel syndrome with diarrhea? Xifaxin with an X may help. Xifaxin Rifaximin is the number one prescribed treatment approved for adults with IBSD. Visit xifaxin.com slash IBSD for the PI or talk to your doctor. Don't use Xifaxin if you have a history of sensitivity to Rifaximin, Rifamycin antibiotic agents, or any components of Xifaxin. Tell your doctor right away if your diarrhea worsens while taking Xifaxin, as this may be a sign of a serious or even fatal condition.