A person with traveler's diarrhea has an infection of the intestines, usually caused by consuming contaminated water or food. The infection is commonly caused by bacterial gastroenteritis, but may also be caused by viral gastroenteritis. Traveler's diarrhea can occur anywhere, but is more common in the underdeveloped world.

Possible causes for traveler's diarrhea include:

• Cholera
• Shigella infection
• Campylobacter enteritis
• Cryptosporidium enterocolitis
• Giardiasis
• Pseudomembranous colitis:
• Clostridium difficile
• Salmonella gastroenteritis
• Traveler's diarrhea due to bacterial infection
• E. coli