Viral gastroenteritis is inflammation of the stomach and intestines caused by a virus. The infection can lead to diarrhea and vomiting. It is sometimes called the "stomach flu."

Viral gastroenteritis is a leading cause of severe diarrhea in both adults and children. Many types of viruses can cause gastroenteritis. The most common ones are:

• Rotavirus, the leading cause of severe gastroenteritis in children. It can also infect adults exposed to children with the virus. Outbreaks may also occur in nursing homes.
• Norwalk virus, which is common among school-age children.

These viruses are often found in contaminated food or drinking water. Symptoms of viral gastroenteritis usually appear within 4 to 48 hours after exposure to the contaminated food or water.

Those with the highest risk for severe gastroenteritis include the young, the elderly, and people who have suppressed immune systems.

• Abdominal pain
• Abdominal cramping
• Diarrhea
• Nausea
• Vomiting

Additional symptoms may include: 

• Unintentional weight loss
• Vomiting blood (very rare)
• Excessive sweating
• Clammy skin
• Muscle pain
• Joint stiffness
• Incontinence
• Fever
• Chills
• Poor feeding

Tests that examine stool samples are used to identify the specific virus or rule out a bacterial cause.