Most cases of travelers' diarrhea are caused by bacterial pathogens which respond slowly to antibiotic treatment.The study was designed to determine the value of rapidly acting loperamide (imodium) combined with curative dose of the poorly absorbed rifaximin in travelers' diarreha treatment.

During short-term study, adult U.S. students in Mexico (n = 310) with acute diarrhea (≥ 3 unformed stools with enteric symptoms) were enrolled in a double-blind, randomized trial wherein they were given rifaximin 200 mg three times a day for 3 days (R) (n = 102), loperamide 4 mg initially followed by 2 mg after each unformed stool not to exceed 8 mg/day for 2 days (L) (n = 104) or both drugs in the same dosage schedule (L/R) (n = 104). The major outcome parameter was time from initiation of therapy until passage of the last unformed stool before becoming well (TLUS).

Inclusion Criteria:

• Inclusion criteria include: IRB approval; signing of a consent form;18 years of age or older, providing of an unformed pre-treatment stool; females must be non-pregnant and not nursing.

Exclusion Criteria:

• 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.