Travelers' diarrhea is the most common illness in persons traveling from resource-rich to resource- poor regions of the world. The fear of developing diarrhea while traveling is common among travelers to any part of the developing world. This concern is realistic; 40 to 60% of travelers to these countries may develop diarrhea. Diarrheal diseases represent one of the five
leading causes of death worldwide. Morbidity and mortality are significant even in the United States where diarrhea is more often than not a "nuisance disease" in the normally healthy individual.