Up to half of all travelers spending two or more weeks in developing countries will experience Travelers' Diarrhea (TD). TD generally strikes during the first week of travel, but may occur at any time during a trip or even after returning home. Some travelers may experience TD more than one time in a single trip, but the condition is rarely life-threatening. Most cases will resolve on their own in three to four days, but if symptoms persist they may be a sign of a more serious infection.