It refers to urgent and frequent passage of loose or watery stools. It can range from a brief annoyance to a severe, dangerous illness. The cause of brief diarrhea is usually an infection, bacteria that produce toxins, or certain drugs.
Mild diarrhea can also occur from emotional upset, an alcohol binge, or certain types of foods.
Travel from one country to another can result in diarrhea within a few days. The cause is bacteria that the local people can resist but the visitor cannot. Most cases of diarrhea resolve on their own. However, a serious complication of long term diarrhea is dehydration. This is excessive loss of body water.