Most people experience frequent, watery bowel movements once or twice a year. This change from the usual pattern of stools is recognized as diarrhea, although many less "formal" names are sometimes used.

For most people, the episode is more an inconvenience than an illness. Symptoms commonly disappear in a short time, and the only important effect is that water and salts are lost from the body.

Sometimes diarrhea lasts for weeks or months, and then it can be an indication of major disease. This...