To most individuals, diarrhea means an increased frequency or decreased consistency of bowel movements; however, the medical definition is more exact than this. In many developed countries, the average number of bowel movements is three per day. However, researchers have found that diarrhea best correlates with an increase in stool weight; stool weights above 300 grams per day generally indicates diarrhea. This is mainly due to excess water, which normally makes up 60-85% of fecal matter. In this way, true diarrhea is distinguished from diseases that cause only an increase in the number of bowel movements (hyperdefecation), or incontinence (involuntary loss of bowel contents). Diarrhea is also classified by physicians into acute, which lasts 1-2 weeks, and chronic which continues for longer than 23 weeks. Viral and bacterial infections are the most common causes of acute diarrhea.

In many cases, acute infectious diarrhea is a mild, limited annoyance. However, worldwide...