 - Exclusion criteria include: diarrhea longer than 72 hours; moderate or severe dehydration, pregnancy or breast feeding, receipt of trimethoprim-sulfamethoxazole, azalide, doxycycline, or a fluoroquinolone in the past week; unstable medical condition; hypersensitivity to rifaximin or rifampin; fever 100.6o F or bloody diarrhea. 