It's possible that traveler's diarrhea may stem from the stress of traveling or a change in diet. But almost always an infectious agent is to blame.

You typically develop traveler's diarrhea after ingesting food or water that's contaminated with organisms from feces. These organisms are infectious agents — including various bacteria, viruses and parasites — that enter your digestive tract and overpower your defense mechanisms, resulting in signs and symptoms of traveler's diarrhea.

The most common cause of traveler's diarrhea is enterotoxigenic Escherichia coli (ETEC) bacteria. These bacteria attach themselves to the lining of your intestine and release a toxin that causes diarrhea and abdominal cramps.

So why aren't natives of high-risk countries affected in the same way? Often their bodies have become accustomed to the bacteria and developed immunity to them.

Jun. 11, 2013

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