Diarrhea is loose, watery stools (bowel movements). You have diarrhea if you have loose stools three or more times in one day. Acute diarrhea is diarrhea that lasts a short time. It is a common problem. It usually lasts about one or two days, but it may last longer. Then it goes away on its own.

Diarrhea lasting more than a few days may be a sign of a more serious problem. Chronic diarrhea -- diarrhea that lasts at least four weeks -- can be a symptom of a chronic disease. Chronic diarrhea symptoms may be continual, or they may come and go.

The most common causes of diarrhea include:

• Bacteria from contaminated food or water
• Viruses such as the flu, norovirus, or rotavirus . Rotavirus is the most common cause of acute diarrhea in children.
• Parasites, which are tiny organisms found in contaminated food or water
• Medicines such as antibiotics, cancer drugs, and antacids that contain magnesium
• Food intolerances and sensitivities, which are problems digesting certain ingredients or foods. An example is lactose intolerance.
• Diseases that affect the stomach, small intestine, or colon, such as Crohn's disease
• Problems with how the colon functions, such as irritable bowel syndrome

Some people also get diarrhea after stomach surgery, because sometimes the surgeries can cause food to move through your digestive system more quickly.

Sometimes no cause can be found. If your diarrhea goes away within a few days, finding the cause is usually not necessary.

People of all ages can get diarrhea. On average, adults In the United States have acute diarrhea once a year. Young children have it an average of twice a year.

People who visit developing countries are at risk for traveler's diarrhea. It is caused by consuming contaminated food or water.

Other possible symptoms of diarrhea include:

• Cramps or pain in the abdomen
• An urgent need to use the bathroom
• Loss of bowel control

If a virus or bacteria is the cause of your diarrhea, you may also have a fever, chills, and bloody stools.

Diarrhea can cause dehydration, which means that your body does not have enough fluid to work properly. Dehydration can be serious, especially for children, older adults, and people with weakened immune systems.

Although it is usually not harmful, diarrhea can become dangerous or signal a more serious problem. Contact your health care provider if you have:

• Signs of dehydration
• Diarrhea for more than 2 days, if you are an adult. For children, contact the provider if it lasts more than 24 hours.
• Severe pain in your abdomen or rectum (for adults)
• A fever of 102 degrees or higher
• Stools containing blood or pus
• Stools that are black and tarry

If children have diarrhea, parents or caregivers should not hesitate to call a health care provider. Diarrhea can be especially dangerous in newborns and infants.

To find the cause of diarrhea, your health care provider may:

• Do a physical exam
• Ask about any medicines you are taking
• Test your stool or blood to look for bacteria, parasites, or other signs of disease or infection
• Ask you to stop eating certain foods to see whether your diarrhea goes away

If you have chronic diarrhea, your health care provider may perform other tests to look for signs of disease.

Diarrhea is treated by replacing lost fluids and electrolytes to prevent dehydration. Depending on the cause of the problem, you may need medicines to stop the diarrhea or treat an infection.

Adults with diarrhea should drink water, fruit juices, sports drinks, sodas without caffeine, and salty broths. As your symptoms improve, you can eat soft, bland food.

Children with diarrhea should be given oral rehydration solutions to replace lost fluids and electrolytes.

Two types of diarrhea can be prevented - rotavirus diarrhea and traveler's diarrhea. There are vaccines for rotavirus. They are given to babies in two or three doses.

You can help prevent traveler's diarrhea by being careful about what you eat and drink when you are in developing countries:

• Use only bottled or purified water for drinking, making ice cubes, and brushing your teeth
• If you do use tap water, boil it or use iodine tablets
• Make sure that the cooked food you eat is fully cooked and served hot
• Avoid unwashed or unpeeled raw fruits and vegetables

NIH: National Institute of Diabetes and Digestive and Kidney Diseases