Diarrhea is loose, watery, and frequent stools. Diarrhea is considered chronic (ongoing or prolonged) when you have had loose or frequent stools longer than 4 weeks.

Diarrhea in adults is usually mild and resolves quickly without complication. In infants and children (especially under age 3), diarrhea is more concerning. Children can become dehydrated fairly quickly.

The most common cause of diarrhea is a mild viral infection that resolves on its own within a few days. This is called viral gastroenteritis or "stomach flu." Viral gastroenteritis often appears in mini-epidemics in schools, neighborhoods, or families.

Food poisoning and traveler's diarrhea are two other common causes. They occur from eating food or drinking water contaminated with bacteria or parasites.

• Malabsorption syndromes -- you are unable to absorb or digest certain nutrients. Common examples include lactose intolerance, gluten malabsorption, and intolerance to specific foods like beans or fruit.
• Inflammatory bowel diseases -- Crohn's disease and ulcerative colitis are two recurring types of diarrhea that are generally bloody and accompanied by abdominal pain.
• Irritable bowel syndrome (IBS) -- a chronic form of stomach upset that gets worse from stress. You generally have alternating diarrhea and constipation.
• Immune deficiency.

Medications can also cause diarrhea, especially antibiotics, laxatives containing magnesium, and chemotherapy for cancer treatment.

• Zollinger-Ellison syndrome
• Nerve disorders like autonomic neuropathy or diabetic neuropathy
• Carcinoid syndrome
• Following gastrectomy (partial removal of the stomach)
• High dose radiation therapy

• Drink plenty of fluid to avoid becoming dehydrated. Start with sips of any fluid other than caffeinated beverages. Milk may prolong loose stools, but also provides needed fluids and nourishment. Drinking milk may be fine for mild diarrhea. For moderate and severe diarrhea, electrolyte solutions available in drugstores are usually best.
• Active cultures of beneficial bacteria (probiotics) make diarrhea less severe and shorten its duration. Probiotics can be found in active culture yogurt and as supplements.
• Foods like rice, dry toast, and bananas may help some.
• Avoid over-the-counter diarrheal medications unless specifically instructed to use one by your doctor. Certain infections can be made worse by these drugs. When you have diarrhea, your body is trying to get rid of whatever food, virus, or other bug is causing it.
• Rest.

If you have a chronic form of diarrhea, like irritable bowel syndrome, try adding bulk to your diet to thicken the stool and regulate bowel movements. Such foods include rice, bananas, and fiber from whole-wheat grains and bran. Psyllium-containing products such as Metamucil or similar products can add bulk to stools.

Call your doctor if:

• You have blood or pus in your stools or if your stool is black.
• You have abdominal pain that is not relieved by a bowel movement.
• You have symptoms of dehydration -- see article on dehydration.
• You have a fever above 101°F or your child has a fever above 100.4°F along with diarrhea.
• You have foul smelling or oily-looking stools.
• You have recently traveled to a foreign country.
• You have eaten with other people who also have diarrhea.
• You have started on a new medication.
• Your diarrhea does not get better in 5 days (2 days for an infant or child) or worsens before that.
• Your child has been vomiting for more than 12 hours. In a newborn (under 3 months), you should call as soon as vomiting or diarrhea begins.

• When did your diarrhea start?
• How long have you had diarrhea?
• What is the color and consistency of your stool?
• Do you have blood in your stool?
• Are you passing large amounts of mucus with your stool?
• What other symptoms do you have?
• Do you have abdominal pain or severe cramping with the diarrhea?
• Do you have fever or chills?
• Are any other family members sick?
• Have you recently traveled out of the country?
• What makes your pain worse? Stress? Specific foods?
• Have you had abdominal surgery?
• What medications do you take? Any recent changes to your medications?
• Do you drink coffee? How much?
• Do you drink alcohol? How much? How often?
• Do you smoke? How much each day?
• Are you on a special diet?

Your doctor will ask you to obtain one or more stool samples in special containers to test for signs of inflammation and infection and to identify the organism causing infection.

• chem-20 (to check electrolytes)
• urine specific gravity
• BUN and creatinine

• Wash your hands often, especially after going to the bathroom and before eating.
• Teach children to not put objects in their mouth.
• When taking antibiotics, try using Lactobacillus acidophilus, a probiotic or healthy bacteria. This helps replenish the good bacteria that antibiotics can kill.

When traveling to underdeveloped areas, follow the steps below to avoid diarrhea:

• Drink only bottled water and DO NOT use ice.
• DO NOT eat uncooked vegetables or fruit without a peel.
• DO NOT eat raw shellfish or undercooked meat.
• DO NOT consume dairy products.