DiarrheaThe definition of diarrhea depends on what is normal for you. For some, diarrhea can be as little as one loose stool per day. Others may have three daily bowel movements normally and not be having what they consider diarrhea. So the best description of diarrhea is "an abnormal increase in the frequency and liquidity of your stools." For simplicity, this section of the Self-Care Advisory only deals with acute, sudden onset diarrhea, as opposed to those with long-term problems.

The basic physiology of acute diarrhea is simple: either not enough fluid is absorbed from the intestines, or the intestines produce too much fluid. The result is a lot more stool liquid then you're used to. Below are some common causes and their characteristics.


Cause Symptoms
Viral (stomach flu) gastroenteritis Nausea, vomiting, watery diarrhea, fever, aches. Usually 1-3 days.
Bacterial infection Diarrhea, fever, chills, sometimes blood or mucus in the stools. Vomiting less common. 
Food intolerance/lactose intolerance Bloating, gas, cramps, loose stools hours after eating dairy products or other offending foods. No other signs of illness or infection. 
Emotional distress Cramping, loose stools, predictable during times of stress.

gastroenteritisThe above is only a partial list; there are literally dozens of different causes.  Most of the time you won’t find out exactly what’s causing an episode of diarrhea, and since most diarrhea goes away by itself, the cause often doesn’t matter.  But you should know how serious it is and what to do about it.  With the exception of infants and some of the complications discussed in When To See Your Doctor, most cases of diarrhea are not serious and can easily be treated at home.

You should note that this list characterizes the most common U.S. causes of diarrhea, not what might exist in other countries.  If you’ve been traveling outside the U.S. recently or plan to soon, check out our topic [Traveler’s Diarrhea] for important health information on its prevention and treatment.

Most types of diarrhea in the U.S. are harmless and will go away by themselves within hours to days.  As long as you don’t get dehydrated, there’s little to worry about.  There are two exceptions, though; bacterial infection and giardiasis.

By now you realize how varied the types and causes of diarrhea are.  Don’t get too confused or worried through --- since the vast majority of diarrhea episodes are the harmless types, the odds are with you.  Just watch for signs of the more serious type infections, and follow the [When To See Your Doctor] advice. 

Infectious Diarrhea

You usually catch infectious types of diarrhea by actually eating microscopic viruses, bacteria, or parasites.  These microbes then flourish in your intestines, causing damage and diarrhea.  But how do the little creatures end up in our mouths in the first place?  The answer is simple, but disgusting:  the offending microbes usually are passed from the diarrhea of others.  For example, those who don’t wash their hands after having bowel movements pass these infections by preparing food, shaking hands or other casual contact.  This mode of transmission can be just as contagious as a cold or respiratory flu.

Non-infectious Diarrhea

Trying to figure out the cause of non-infectious diarrhea can be difficult.  If there’s an obvious relationship between diarrhea and cramping and the ingestion of dairy products a few hours earlier, then lactose intolerance is a very likely diagnosis.  If your problems are predictably aggravated by stressful situations or other emotional or situational events, then Irritable Bowel Syndrome is more likely (click here for more information on [Irritable Bowel Syndrome]).

Prevention of these conditions is directed at simply avoiding the triggering events --- such as taking a Lactose-absorption enzyme with dairy products, or avoiding certain foods or spices which tend to trigger loose stools for you.  Trying to stay away from stressful circumstances is easy advise to give, but hard to achieve from a practical stand point.  See the topic area [Irritable Bowel Syndrome] for more detailed instructions on treatment.  

See a doctor if your diarrhea lasts more than a couple of days, if you have a high fever or if you notice blood in your stools. If you think you might be dehydrated or if you have severe stomach pain, call a doctor right away or go to the nearest emergency room.

More than diarrhea on our Self Care Home Page



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