How to Head Off Montezuma's Revenge

Whether you call it Delhi belly or Montezuma's revenge, travelers' diarrhea is the most common illness among visitors to developing countries, affecting 40 percent of visitors to Africa, Latin America, and southern Asia. While most sufferers beat the bug in a couple of days, 10 percent develop irritable bowel syndrome.

Contrary to popular belief, it's usually food—not water—that's the culprit, says Herbert DuPont, a specialist in infectious disease at Baylor College of Medicine in Houston. He recommends avoiding food that is both room temperature and moist: "It should have a skull and crossbones on it," he says. Instead, choose foods that are peeled, that are served steaming hot, or whose high sugar content inhibits microbes from multiplying. And don't let your guard down on the plane ride home. DuPont warns that airplane food can be contaminated if a flight originates in a high-risk country.

Once popular in the 1960s, prophylactic antibiotics to ward off travelers' diarrhea are making a comeback. Researchers have developed a skin-patch vaccine that has proved highly effective at foiling the bug, but it's not slated to hit the market for a couple of years. Until then, ask your doctor to prescribe Xifaxan, a gastrointestinal antibiotic, or maintain a regimen of eight tablets of Pepto-Bismol per day while traveling to keep symptoms at bay. For more tips on staying well on the road, check out the travelers' health section of the CDC Web site.