Diarrhea is one of the most common illnesses in all age groups and is second only to the common cold as a cause of lost days of work or school. Children younger than 3 years have about 2 episodes of diarrhea per year. Older children and adults have about 1 bout with diarrhea a year. Diarrhea and related complications can cause severe illness. The most significant cause of severe illness is loss of water from the diarrhea, which is often accompanied by vomiting.
Fluids pass through the body before they can be absorbed in the intestine.
When a person's ability to drink fluid to compensate for the water lost with diarrhea and vomiting is impaired, dehydration can result. Most deaths from diarrhea occur in the very young and the elderly, whose health may be put at risk from a moderate amount of dehydration. Various definitions of diarrhea Chronic diarrhea is seen in people who have had loose or liquid stool for over 2 weeks. Acute enteritis means inflammation of the intestine. This description is often used interchangeably with diarrhea.