Bacteria cause 50 to 80% of travelers' diarrheic diseases. The most important pathogens include enterotoxigenic Escherichia coli (ETEC), campylobacteria, salmonellae and shigella. Diarrheic viruses cause 5 to 25% and protozoa less than 10% of travelers' diarrheas. Hand and food hygiene constitute the main preventive measures. Treatment of traveler's diarrhea is based on rehydration therapy and rest. Antimicrobial therapy is required only in cases with exceptionally severe symptoms.