We have changed our visitation policy for the safety of our patients and staff. Click here for the updated visitation policy and click here for information about COVID-19.

Lahey Health is now part of Beth Israel Lahey Health

by Shannon DW
(Stomach Flu; Stomach Bug)


Viral gastroenteritis is an infection of the intestines and stomach.

The Intestines
Copyright © Nucleus Medical Media, Inc.


It is caused by one of many viruses. The virus can spread easily through fluids of the mouth and nose. It is passed to surfaces and objects where it can live for hours. People touch the surface with the virus then touch their mouth, nose, or eyes. This is the easiest way for the virus to spread. The virus may also be spread through food or water that has the virus. Some common viruses include:

Risk Factors

Children and older adults are more likely to get this infection. It can spread easily in:

  • Child care centers
  • Nursing homes
  • Cruise ships
  • College dormitories
  • Campgrounds


The symptoms begin 1 to 2 days after you have contact with the virus. They usually last 1 to 2 days.

Symptoms may include:

  • Watery diarrhea
  • Nausea
  • Vomiting
  • Abdominal cramps
  • Fever
  • Muscle aches
  • Headache


You will be asked about your symptoms and past health. A physical exam may be done. The doctor will suspect a virus based in symptoms.

The stool may need to be tested if the illness is severe or not passing. It will help to find the exact cause of the infection.


Antibiotics are not helpful against a virus. The infection will pass on its own. There are steps to help you feel more comfortable. It is also important to prevent dehydration.

  • Drink plenty of fluids. You can lose a lot of fluid through vomit and diarrhea. Taking in fluids will help prevent dehydration.
    • Take small sips of water or suck on ice chips if you are having trouble keeping fluids down.
    • Drink clear soda or sports drinks.
    • Give your child an oral rehydration solution instead of water. You can buy them or make them at home. One example is Pedialyte.
  • When you feel able slowly start to eat bland foods. Toast, crackers, scrambled eggs, or potatoes are good options.
    • Avoid dairy products, caffeine, fast foods, and fatty or spicy foods until you feel better.
    • If a sick infant was breastfeeding, continue to breastfeed.
    • If your baby is bottle-fed, give them an oral rehydration solution or formula.
    • Avoid giving children juice or jello. They do not help to increase fluids levels in the body.
  • Rest as needed.

Most gastroenteritis will only need home care. However, call your doctor if you:

  • Cannot keep fluids down for 24 hours
  • Vomit blood
  • Have bloody diarrhea
  • Have a fever above 101°F (98°C)
  • Vomit for more than 2 days
  • Have signs of dehydration:
    • Lightheadedness
    • Excessive thirst
    • Dry mouth
    • Dark urine
    • Little or no urine

Call your doctor if your child:

  • Is under 6 months of age
  • Has a fever of 102°F (38.8°C) or higher
  • Seems tired or irritable
  • Has trouble feeding
  • Has bloody diarrhea
  • Has stomach pain
  • Has signs of dehydration:
    • Unusual drowsiness
    • Dry lips and mouth, or sunken eyes
    • No tears when crying
    • Dark urine
    • Not urinating very much (for example, no wet diaper in 3 hours)
    • Feeling thirsty, but vomiting after drinking fluids


To help reduce your chances of viral gastroenteritis:

  • If possible, avoid contact with people who have the condition.
  • Always wash your hands often and thoroughly. Use warm water and soap.
  • Help your children wash their hands thoroughly.
  • Use bleach to disinfect contaminated surfaces in your home (toilet, sink faucet in bathroom).
  • Avoid sharing personal items such as toothbrushes, towels, and drinking glasses.
  • Take special care when traveling to countries that are more likely to have contaminated food and water. Only drink sealed bottled water, avoid ice cubes and brushing your teeth with tap water, and avoid eating raw foods, including vegetables.


Family Doctor—American Academy of Family Physicians  https://www.familydoctor.org 

Centers for Disease Control and Prevention  https://www.cdc.gov 


Alberta Health  http://www.health.alberta.ca 

HealthLink BC  https://www.healthlinkbc.ca 


Norovirus. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/norovirus. Updated October 5, 2018. Accessed December 12, 2018.

Norovirus infection. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T114466/Norovirus-infection  . Updated July 31, 2017. Accessed December 12, 2018.

Rotavirus gastroenteritis. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T114180/Rotavirus-gastroenteritis  . Updated September 26, 2018. Accessed December 12, 2018.

Viral gastroenteritis. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/digestive-diseases/viral-gastroenteritis. Updated May 2018. Accessed December 12, 2018.

Revision Information

  • Reviewer: EBSCO Medical Review Board Marcie L. Sidman, MD
  • Review Date: 11/2018
  • Update Date: 12/12/2018