Diarrhea in the international traveler

International travelers to developing countries have a 40% risk of developing a diarrheal illness, usually acute and occasionally chronic. Preventive measures, including diet and lifestyle modifications, are highly recommended but may not be sufficient. Prophylaxis with bismuth subsalicylate or an antimicrobial should be considered in travelers with immunodeficiencies, co-morbid conditions, achlorhydria, or those who cannot afford a loss of time. Oral rehydration is the primary goal of therapy. Bismuth-subsalicylate is a first-line agent for treatment of milder cases with less than three watery bowel movements per day and prominent nausea. Use of an antibiotic is indicated for more severe cases or in the presence of fever, dysentery, or severe dehydration. A short course of a quinolone is highly effective, safe and well tolerated. Antimicrobial resistance among enteropathogens is growing and appropriate therapeutic modifications should be considered according to specific geographic areas. Metronidazole may be empirically added in those cases that do not respond to quinolones. Specific guidelines for particular pathogens are highlighted.