Diarrhea with its loose, watery stools, frequent trips to the bathroom and other unpleasant symptoms is a digestive disorder that virtually everyone has or will eventually experience. It is estimated that up to 5 percent of US population is affected by diarrhea at any given time with the average adult experiencing a bout of diarrhea about four times a year. People of all ages can get diarrhea but it can be particularly dangerous in children and the elderly because it can rapidly cause dehydration and needs to be treated promptly to avoid serious health problems.

For healthy adults the most common type of diarrhea, acute or short-term, usually lasts a few days at most and goes away on its own without any special treatment. However, if diarrhea persists beyond 1 week or extreme dehydration is suggested by excessive thirst, dry mouth and skin, little or no urination, severe weakness, dizziness or lightheadedness, medical attention is needed. Also get medical help if there is severe, persistent abdominal or rectal pain, bloody or black, tarry stools, or a temperature of more than 101 F. Chronic or long-term diarrhea where the symptoms are continuous or reoccur frequently is an indication of more serious underlying problems such as irritable bowel syndrome, inflammatory bowel disease, chronic infection, or malabsorption of nutrients.

The signs and symptoms associated with diarrhea often include:
Frequent loose, watery stools
An urgent need to use the bathroom
Abdominal cramps
Abdominal pain
Fever
Bloody stools
Bloating,
Nausea and vomiting

Causes of Diarrhea
Chronic Diarrhea
Treatment & Prevention of Diarrhea

Causes

Most commonly, acute diarrhea is the result of an inflammation of the intestinal tract. The inflammation can be the result of pathogenic bacteria overgrowth (often after antibiotic treatment, a viral or parasitic infection or irritation caused by medications or foods) or a viral or parasitic infections and irritations caused by medications and certain foods including artificial sweeteners. Normally, the food you eat remains in liquid form during most of the digestive process up to and including the small intestine. At the point where food passes into and through the colon most of the fluids are absorbed and what remains is a semisolid stool. Inflamation can disrupt the normal processes of the digestive system causing food and fluids to pass too quickly or in to large an amount (or both) through the colon. As a result, the fluids aren't sufficiently absorbed and the result is a watery bowel movement. The most common causes of the intestinal infection or irritation that causes diarrhea include:

Bacteria
Contaminated food or water can introduce pathogenic bacteria into your intestinal tract. Common bacterial causes of diarrhea include campylobacter, salmonella, shigella and Escherichia coli. Normally your intestinal tract is home to billions of beneficial bacteria that perform vital functions in the digestion of food. These beneficial bacteria compete with pathogenic bacteria and help keep them in check. When a harmful strain like E. coli is able to overwhelm the body’s beneficial (also known as probiotic) bacteria and grow out of control they can injure the intestinal walls are irritate the system.

Viruses
Rotavirus and adenovirus are common causes of diarrhea in young children as direct contact easily spreads these viruses.

Medication
Diarrhea can be a side effect of many medications, particularly antibiotics. Antibiotics disturb the natural balance of beneficial bacteria (probiotics) in your intestines leaving you vulnerable to infection. Some high blood pressure medications, cancer drugs and antacids containing magnesium can cause irritation and diarrhea.

Food intolerances and allergies
Some people are unable to digest a component of food, such as lactose, the sugar found in milk and milk products. In addition, the artificial sweeteners sorbitol and mannitol found in chewing gum and other sugar-free products can cause irritation and diarrhea. Many otherwise healthy people may have some difficulty with these sweeteners. When an allergy is present one strategy is to avoid the offending food initially, then try slowly reintroducing it to the diet along with the use of digestive enzymes.

Previous surgery or radiation of the abdomen or gastrointestinal tract
Some people develop diarrhea after stomach surgery or removal of the gallbladder. The reason may be a change in how quickly food moves through the digestive system after stomach surgery or an increase in bile in the colon that can occur after gallbladder surgery.

Parasites
Parasites like Giardia lamblia and cryptosporidium can cause diarrhea.

Travelers Diarrhea
People who visit foreign countries are at risk for traveler's diarrhea, which is caused by eating food or drinking water contaminated with bacteria, viruses, or in some cases, parasites. Traveler's diarrhea is a particular problem for people visiting developing countries. Visitors to the United States, Canada, most European countries, Japan, Australia, and New Zealand are not as much at risk.

Chronic Diarrhea

In many cases, the reason for a particular attack diarrhea is hard to determine and as long as the diarrhea goes away on its own an extensive search for the cause is not necessary. However, Chronic Diarrhea, where symptoms are continuous or frequently re-occur, can be a signal of
underlying serious health issues that need to be addressed. Diagnosis of the cause of chronic diarrhea can start with a careful review of the person’s medical history and blood and stool tests. Stool cultures may be used to test for bacteria and to detect parasites. Other procedures can include X-rays and endoscopy. Endoscopy is a procedure in which a tube is inserted into the mouth or rectum so that the gastroenterologist can look at the intestine from the inside. Since chronic diarrhea is one of the most common symptoms of food allergy, testing for this shouldn’t be overlooked.

Chronic diarrhea can have a substantial impact on quality of life and overall health. At its mildest, the condition may be an inconvenience; at its worst, it may be disabling and even life-threatening. The two common classifications often associated with chronic diarrhea are Irritable Bowel Syndrome and Inflammatory Bowel Disease.

Irritable Bowel Syndrome (IBS)
Irritable Bowel Syndrome (IBS) is a condition often associated with frequent stools, alteration in bowel habits, abdominal pain and diarrhea (although many with IBS have constipation rather than diarrhea or alternate between the two). Emotional or physiological distress is often present and IBS is characterized as a condition with this persistent group of symptoms where no anatomic or organic diseases can be detected.

Inflammatory Bowel Disease (IBD)
Pain with defecation, unintentional weight loss, fever, abdominal cramping and chronic bloody diarrhea suggests Inflammatory Bowel Diseases such as ulcerative colitis and Crohn's disease. Ulcerative colitis is primarily an inflammation of the colon and rectum. Crohn's disease, or regional enteritis, is inflammation and deep ulcer formation in the lining of any region of the intestinal tract.