Overview
Viral gastroenteritis is an intestinal infection that includes signs and symptoms such as watery diarrhea, stomach cramps, nausea or vomiting, and sometimes fever.
The most common way to develop viral gastroenteritis — often called stomach flu — is through contact with an infected person or by consuming contaminated food or water. If you’re otherwise healthy, you’ll likely recover without complications. But for infants, older adults and people with compromised immune systems, viral gastroenteritis can be deadly.
There’s no effective treatment for viral gastroenteritis, so prevention is key. Avoid food and water that may be contaminated and wash your hands thoroughly and often.
Symptoms
Although it’s commonly called stomach flu, gastroenteritis isn’t the same as influenza. The flu (influenza) affects only your respiratory system — your nose, throat and lungs. Gastroenteritis, on the other hand, attacks your intestines, causing signs and symptoms such as:
- Watery, usually nonbloody diarrhea — bloody diarrhea usually means you have a different, more severe infection
- Nausea, vomiting or both
- Stomach cramps and pain
- Occasional muscle aches or headache
- Low-grade fever
Depending on the cause, viral gastroenteritis symptoms may appear within 1-3 days after you’re infected and can range from mild to severe. Symptoms usually last just a day or two, but occasionally they may last up to 14 days.
Because the symptoms are similar, it’s easy to confuse viral diarrhea with diarrhea caused by bacteria, such as Clostridioides difficile, salmonella and Escherichia coli, or parasites, such as giardia.
Viral gastroenteritis
The stomach, small intestine and large intestine (colon) are part of your digestive tract, which processes the foods you eat. Viral gastroenteritis is an inflammation of these organs caused by a virus.
When to see a doctor
If you’re an adult, call your health care provider if:
- You’re not able to keep liquids down for 24 hours
- You’ve been vomiting or having diarrhea for more than two days
- You’re vomiting blood
- You’re dehydrated — signs of dehydration include excessive thirst, dry mouth, deep yellow urine or little or no urine, and severe weakness, dizziness or lightheadedness
- You notice blood in your bowel movements
- You have severe stomach pain
- You have a fever above 104 F (40 C)
For infants and children
See your child’s health care provider right away if your child:
- Has a fever of 102 F (38.9 C) or higher
- Seems tired or very irritable
- Is in a lot of discomfort or pain
- Has bloody diarrhea
- Seems dehydrated — watch for signs of dehydration in sick infants and children by comparing how much they drink and urinate with how much is normal for them, and watching for signs such as a dry mouth, thirst and crying without tears
If you have an infant, remember that while spitting up may be an everyday occurrence for your baby, vomiting is not. Babies vomit for a variety of reasons, many of which may require medical attention.
Call your baby’s doctor right away if your baby:
- Has vomiting that is frequent
- Hasn’t had a wet diaper in six hours
- Has bloody stools or severe diarrhea
- Has a sunken soft spot (fontanel) on the top of his or her head
- Has a dry mouth or cries without tears
- Is unusually sleepy, drowsy or unresponsive
