Symptoms depend on the cause and how long the condition has been present, among other factors. The condition usually starts suddenly, sometimes with a loss of appetite, nausea, cramping and growling or rumbling sounds from gas moving through the intestines and diarrhea. If there has been too much loss of fluids, dehydration, headaches, irritability and shock may occur. Other signs include muscle aches, weakness and feeling sick.

Causes and Risk Factors

Although the cause is not always identified, some possibilities include:

• Infections
• Viruses
• Intestinal parasites
• Chemical toxins found in plants, seafood or contaminated food
• Ingesting heavy metals (such as arsenic, lead, mercury or cadmium)
• Drugs that alter the digestive system

To form a diagnosis, doctors will look for a cause, such as the patient's having:

• Eaten potentially contaminated food
• Drunk untreated surface water
• Recently traveled
• Contact with people who have similar symptoms

Other tests may include:

• Samples of stool or vomit to see if bacteria, viruses or parasites are present
• Blood tests
• Sigmoidoscopy to rule out other problems

Treatment includes:

• Bed rest
• Giving strained broth or bouillon
• Giving bland foods (e.g., cereal, gelatin, bananas or toast)
• Drugs may also be given to stop vomiting or diarrhea. Antibiotics may also be given if an infection is suspected.