Diarrhea is one of the most common health problems among travelers. Although enterotoxigenic Escherichia coli is implicated most commonly, enteroaggregative E. coli has recently been described as a major pathogen. Shigella, Campylobacter, and Salmonella organisms are less common causes of acute diarrhea, and intestinal protozoa are typical causes of protracted diarrhea. Although education is the mainstay of prevention measures, behavior modification has been shown to be difficult. Chemoprevention is rarely required with the availability of effective treatment, but there has been some interest in the use of vaccines. Maintenance of hydration is most important in children. In addition to bismuth preparations and loperamide, newer agents being developed for symptomatic relief include zaldaride maleate and racecadotril. Fluoroquinolones effectively treat severe traveler’s diarrhea, and even a single dose may be sufficient. However, with the emergence of resistance, particularly in Campylobacter infection, other agents are required; interest has focused on azithromycin and rifaximin.