Norovirus: Symptoms, Treatment, Prevention & Care
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Introduction
This guide explains norovirus symptoms, treatment, prevention, and when to seek care. It also covers hydration, warning signs, home cleaning, and food safety.
Norovirus often causes sudden vomiting and diarrhea 5,7. Most people get better within one to three days 3,5.
Frequent vomiting and diarrhea can cause dehydration 5. Oral rehydration is the main treatment for norovirus illness 3,4.
Overview: What Norovirus Is
Norovirus is a very contagious virus that causes acute gastroenteritis 5. Acute gastroenteritis means sudden inflammation of the stomach or intestines 5.
People often call norovirus the “stomach flu” or “stomach bug” 5. However, norovirus has no biological link to influenza viruses 3.
Influenza causes a respiratory illness rather than gastroenteritis 6. Learn more in our [Influenza symptoms and care guide](/conditions/influenza-symptoms-treatment-prevention-care-9de2b1).
Norovirus is a leading cause of vomiting, diarrhea, and foodborne illness in the United States 2,5. People of all ages can become infected and sick 5.
There are many norovirus types, so infection can happen more than once 5. Infection with one type may not protect against another type 5.
Most infections are brief, but fluid loss can become serious 5. Young children and older adults face a higher risk of dehydration 3,5.
People with weakened immune systems may also develop severe illness 5. Other health conditions can raise the risk of severe dehydration 7.
Causes: How Norovirus Spreads
Norovirus mainly spreads through the fecal-oral route 3. This route involves virus from stool reaching another person’s mouth 3.
Direct contact and contaminated food or water can spread the virus 3,5. Contaminated objects and surfaces can also cause infection 3,5.
Tiny airborne droplets from vomit can spread norovirus 3. These droplets may also contaminate nearby surfaces 4.
Common routes of transmission
Norovirus can spread through several common situations:
Direct contact can spread norovirus while someone cares for a sick person 5.
Sharing food or utensils with an infected person can spread the virus 5.
Food handled by an infected person may become contaminated 3,5.
Contaminated food, drinking water, or ice can cause infection 3.
Touching a contaminated object may transfer the virus to the mouth 5.
Airborne droplets from vomit may spread virus particles nearby 3,4.
Virus may be present in vomit or stool before illness begins 1. It can remain in stool for at least two weeks after recovery 1,5.
Food containing norovirus may look, smell, and taste normal 1. Raw oysters are a frequent source because they collect particles from contaminated water 3.
Ready-to-eat foods may become contaminated during unsafe handling 3. Examples include salads and sandwiches touched by a sick food handler 3.
Common outbreak settings
Norovirus outbreaks often occur where people live or gather closely 3. Common outbreak settings include the following places:
Schools and child care centers may experience outbreaks 7.
Hospitals and nursing homes are also common outbreak settings 7.
Dormitories, camps, hotels, and cruise ships may have outbreaks 3.
Other crowded settings can allow people to infect each other easily 3.
Virus on objects may remain during and after an outbreak 3. This contamination can become a source of further infection 3.
People at higher risk
Anyone can become infected with norovirus 5. Some people face a higher risk of severe infection or dehydration 3,5.
Groups needing close monitoring include the following people:
Young children may become dehydrated from repeated vomiting and diarrhea 3,5.
Older adults may also need medical attention for dehydration 3,7.
People with weakened immune systems face a higher risk of severe infection 5.
People with other illnesses may become severely dehydrated 5,7.
Norovirus infection can become severe during pregnancy 7.
Symptoms and Typical Timeline
Norovirus symptoms often begin suddenly 7. Vomiting or diarrhea may occur many times during one day 5.
Most common norovirus symptoms
The most common norovirus symptoms affect the stomach and intestines 5. They may include the following signs:
Sudden vomiting is a common symptom 3,5.
Diarrhea is often watery or loose 3,7.
Norovirus diarrhea usually does not contain blood 3.
Nausea often occurs with vomiting or diarrhea 3,5.
Stomach pain and abdominal cramps are common 3,5.
A low-grade fever may occur 3,7.
Headache and body aches may develop 5.
Chills and muscle aches may also occur 4.
Some people develop a general feeling of illness 7.
Children may vomit more often than adults 6. Adults may experience more diarrhea than children 6.
Some infected people do not develop symptoms 7. However, they can still spread the virus to other people 7.
Incubation period and illness duration
The incubation period is the time between exposure and the first symptoms. Norovirus symptoms usually begin 12 to 48 hours after exposure 3,5.
Most people fully recover within one to three days 3,5. People with weakened immune systems may experience a longer illness 4.
Recovery does not immediately end the risk of spread. Virus can remain in stool for two weeks or longer after recovery 1,5.
How to recognize dehydration
Dehydration is the loss of body fluids 5. Repeated vomiting and diarrhea can cause it 5.
Watch for these possible signs of dehydration:
Urination may become less frequent than usual 5.
Urine may look darker than usual 6.
The mouth or throat may feel dry 5,7.
Standing may cause dizziness 5.
Weakness or tiredness may occur 6,7.
Children may cry with few or no tears 5,7.
Children may become unusually sleepy or fussy 5,7.
Severe dehydration can cause serious problems 5. It may require hospital care and fluids given through a vein 5.
Treatment and Recovery at Home
Supportive care is the main norovirus treatment 3. Supportive care manages symptoms while the body recovers.
Replacing lost fluids is the main goal 3,4. There is no specific medicine that treats the infection itself 5.
Replacing fluids and electrolytes
Oral rehydration therapy is the main treatment for fluid loss 3,4. It involves drinking fluids to replace losses from vomiting and diarrhea 5.
Take small sips often if nausea makes drinking difficult 6. Slow drinking may be easier to keep down 6.
Over-the-counter oral rehydration fluids are most helpful for mild dehydration 5. They replace fluids and important minerals lost during illness 5.
Adults may also drink broth or sports drinks 8. However, sports drinks may not replace every important mineral 5.
Drinks with lots of sugar can make diarrhea worse 8. Avoid drinks containing caffeine or alcohol during recovery 5,8.
Continue watching for less urine, dry mouth, dizziness, and unusual tiredness 5,7. These signs may point to dehydration 5,7.
Eating while recovering
Ease back into eating as nausea and vomiting improve 8. Try small amounts of food more often 8.
Bland foods may be easier to digest during recovery 8. Some examples include the following foods:
Crackers and toast may be easier to tolerate 8.
Rice, bananas, and applesauce are other bland choices 8.
Small amounts of chicken may work as recovery continues 8.
Gelatin is another option listed for early recovery 8.
Stop eating if nausea returns 8. Continue trying to replace lost fluids 3,5.
Mayo Clinic advises avoiding dairy and fatty foods for a few days 8. It also advises avoiding highly seasoned foods, caffeine, alcohol, and nicotine 8.
Medicines, antibiotics, and testing
Antibiotics do not treat norovirus 3,5. They work against bacteria rather than viruses 5.
A healthcare professional may recommend medicine for nausea or diarrhea in some adults 8. These medicines may support rehydration for some adults 3.
Adults should ask a clinician whether a symptom medicine is suitable. These medicines are not routinely recommended for children with acute gastroenteritis 3.
Norovirus is generally diagnosed from its symptoms 3. Routine testing is usually not needed 4,6.
A clinician may consider stool testing for someone with a weakened immune system 8. Testing also helps public health teams investigate groups of linked illnesses 3.
When to See a Doctor
Most people recover without specific medical treatment 7. However, dehydration and unusual symptoms may need medical evaluation.
Severe dehydration and drinking problems
Call a healthcare professional if severe dehydration is suspected 5. Severe dehydration may require hospital treatment and intravenous fluids 5.
Intravenous fluids are fluids given through a vein 5. They may be needed when someone cannot drink enough 8.
Contact a healthcare professional if severe vomiting prevents enough fluid intake 7,8. Frequent vomiting can make hydration difficult 5,6.
Possible dehydration signs include reduced urine, dry mouth, dizziness, and marked tiredness 5,7. Few tears or unusual sleepiness may signal dehydration in children 5,7.
Other reasons to contact a healthcare professional
Contact a healthcare professional for these symptoms or situations:
Seek medical attention if diarrhea continues for several days 7.
Call a healthcare professional if vomiting becomes severe 7.
Seek medical attention if stool contains blood 7.
Seek medical attention for significant stomach pain 7.
Call a healthcare professional if dehydration develops 7.
Blood in stool does not fit typical norovirus illness 4. It needs further medical investigation 4.
Marked or focused abdominal tenderness also needs further investigation 4. These findings may point to another cause 4.
Prolonged symptoms may lead a clinician to consider another infection 4. Stool studies may help when symptoms continue or another cause seems likely 4.
Guidance for higher-risk people
Young children and older adults can become severely dehydrated 3,7. People with weakened immune systems or other illnesses may also need medical attention 5,7.
Norovirus infection can become severe in pregnant people 7. These groups need close monitoring for signs of fluid loss 5,7.
Call a healthcare professional if severe dehydration is suspected 5. A clinician may assess hydration and decide whether intravenous fluids are needed 4,5.
Prevention: How to Stop Norovirus Spread
Norovirus prevention relies on handwashing, safe food handling, and prompt cleaning 1,5. These steps also help reduce household spread 1.
Handwashing and staying home
Wash hands with soap and running water for at least 20 seconds 1,5. This is especially important after toilet use or diaper changes 1.
Wash again before eating or preparing food 1. Also wash before handling food or giving medicine 1.
Hand sanitizer alone does not work well against norovirus 1. It may be used in addition to handwashing 1.
Sanitizer should not replace soap and running water 1. Handwashing remains the preferred choice 1.
While sick, do not prepare or handle food 1. Do not care for other people during this time 1.
Wait at least 48 hours after symptoms stop before resuming these tasks 1. Stay home during illness and for 48 hours after symptoms end 5,7.
Keep using careful hygiene after that period. Norovirus may remain in stool for two weeks or longer 1,5.
Food preparation and shellfish safety
Wash fruits and vegetables well before preparing or eating them 1. Cook oysters and other shellfish thoroughly 1.
Quick steaming may not heat shellfish enough to destroy norovirus 1. Keep raw oysters away from food that is ready to eat 1.
Separate raw oysters in shopping carts and refrigerators 1. Use separate cutting boards when preparing them 1.
Clean kitchen tools, counters, and cutting boards after handling shellfish 1. Throw away food that may contain norovirus 1.
Food containing norovirus may still look and smell normal 1. Its taste may also seem normal 1.
Disinfecting surfaces after illness
Clean and disinfect the entire affected area after vomiting or diarrhea 1. Do this as soon as possible 1.
Use these steps when cleaning a contaminated area:
Wear rubber or disposable gloves during cleanup 1.
Use paper towels to wipe the entire affected area 1.
Place used paper towels inside a plastic trash bag 1.
Use an EPA-registered product effective against norovirus 1.
An appropriately prepared chlorine bleach solution is another listed option 1.
Follow the disinfectant label for correct use 1.
Leave bleach disinfectant on the area for at least five minutes 1.
Clean the area again with soap and hot water 1.
Remove the trash and wash hands with soap and water 1.
Virus particles may reach toilets, sinks, tables, chairs, and beds 4. These nearby surfaces may also need careful cleaning 4.
Washing contaminated laundry
Remove clothing or linens contaminated with vomit or stool 1. Wash them as soon as possible 1.
Follow these steps when handling contaminated laundry:
Wear rubber or disposable gloves while handling the items 1.
Handle each item carefully without shaking it 1.
Wash items with detergent and hot water 1.
Use the longest available washing cycle 1.
Machine-dry items at the highest available heat setting 1.
Wash hands with soap and water afterward 1.
Conclusion
Most norovirus infections improve within one to three days 3,5. Replacing lost fluids remains the main part of norovirus treatment 3,4.
Watch closely for reduced urine, dry mouth, dizziness, and unusual sleepiness 5,7. Call a healthcare professional if severe dehydration is suspected 5.
Seek medical attention for severe vomiting, bloody stool, or significant stomach pain 7. Diarrhea lasting several days also needs medical attention 7.
Wash hands with soap and water for at least 20 seconds 1. Hand sanitizer should not replace proper handwashing 1.
Avoid food preparation and caregiving for at least 48 hours after symptoms stop 1. Continue careful hygiene because the virus may remain in stool longer 1,5.
Safe food handling, prompt disinfection, and careful laundry practices can limit norovirus spread 1. These steps can help protect other people at home and in shared settings 1,3.
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