Medically reviewed by Christopher McGee, MD  |  Last Reviewed: September 2026

Quick Answer Norovirus is one of the most common causes of what people call a “stomach bug” or “stomach flu.” It often causes sudden vomiting, watery diarrhea, stomach cramps, and nausea and usually lasts 1 to 3 days. Most people recover at home with rest and fluids, but it’s important to seek care if you or your child cannot keep liquids down, shows signs of dehydration, or symptoms are not improving.

What’s Actually Making You Sick

If you’ve ever had a sudden, miserable bout of vomiting and diarrhea and called it a “stomach bug” or “stomach flu,” there’s a good chance the real cause was norovirus — an extremely contagious virus that inflames the stomach and intestines, a condition doctors call acute gastroenteritis. According to the CDC, it’s the single most common cause of this kind of illness in the United States, and it takes only a tiny amount of virus to make you sick. It spreads through contaminated food or water, close contact with someone who’s sick, or touching a contaminated surface and then your mouth.

The terms people use for it get thrown around loosely, though, and they don’t all mean the same thing:

Term	What It Actually Means
“Stomach bug”	An informal, catch-all phrase for any short illness causing vomiting and diarrhea — could be norovirus, another virus, or food poisoning
“Stomach flu”	A common nickname for viral gastroenteritis. It has nothing to do with the influenza virus, despite the name
Norovirus	A specific, highly contagious virus — the most common actual cause behind most “stomach bug” and “stomach flu” cases
Rotavirus	A different specific virus that causes similar symptoms, but mostly affects infants and young children

In short: if you or your doctor says “stomach bug” or “stomach flu,” there’s a good chance the actual culprit is norovirus.

Norovirus Symptoms and How It Progresses

Norovirus symptoms tend to hit fast and hard. The hallmark is a sudden, forceful combination of vomiting and diarrhea, often along with:

• Sudden, often forceful vomiting
• Watery diarrhea
• Stomach cramping or pain
• Nausea
• Low-grade fever, chills, or body aches
• Headache and fatigue

Kids tend to vomit more, while adults tend to get more diarrhea — though it’s common to get a mix of both, regardless of age.

How long does norovirus last?

For most people, norovirus runs its course in just 1 to 3 days. Symptoms are intense but short — the worst of the vomiting usually eases within the first 24 hours, with diarrhea sometimes lingering a bit longer. Symptoms typically show up 12 to 48 hours after exposure, which is part of why the virus spreads so effectively: you can be carrying it before you have any idea you’re sick. Young children, older adults, and people with weakened immune systems can occasionally have symptoms that last longer.

How long are you contagious?

Longer than you’d think. You’re contagious before symptoms even start, throughout the illness, and for up to 48 hours after you feel completely back to normal — with some people continuing to shed the virus for up to two weeks. That extended window is exactly why norovirus tends to move through households, schools, workplaces, and even cruise ships in waves.

How It Spreads — and Who’s at Risk

It doesn’t take much virus to make you sick, and norovirus spreads through a surprising number of everyday moments:

• Direct contact with someone who’s sick
• Eating food prepared or handled by an infected person
• Drinking contaminated water
• Touching a contaminated surface (doorknobs, faucets, shared remotes) and then touching your mouth
• Sharing food, drinks, or utensils with someone who’s infected

That’s a big part of why it moves so quickly through households, schools, and workplaces once it arrives. And it doesn’t discriminate by age: while norovirus is often talked about in the context of school-age kids, adults get it just as easily — some of the best-known outbreaks happen in settings full of adults, like cruise ships, restaurants, offices, and weddings. If someone in your household or workplace has it, assume everyone who was in contact is at real risk, regardless of age.

Treating Norovirus at Home

There’s no medication that cures norovirus — it’s a virus, so antibiotics won’t help, and it generally has to run its course. Treatment is all about supportive care:

• Rest as much as possible
• Sip fluids frequently rather than drinking large amounts at once
• Ease back into eating gradually once vomiting slows down
• Wash your hands thoroughly and often to protect the rest of your household

What should you eat and drink?

Stick to the basics while your stomach settles, then ease back in gradually:

• Water, oral rehydration solutions (like Pedialyte), clear broths, and diluted juice
• Bland foods once you can keep liquids down: toast, crackers, rice, bananas, plain oatmeal
• Small, frequent sips and bites rather than large meals
• Avoid dairy, caffeine, alcohol, and fatty or spicy foods until you’re feeling fully better — they can aggravate an already irritated stomach

Signs of Dehydration to Watch For

• Dry mouth or unusual thirst
• Little or no urination, or urine that’s noticeably dark
• Dizziness or lightheadedness, especially when standing
• In children: no tears when crying, or a sunken soft spot in infants
• Unusual fatigue or confusion

 

Need to be seen today? If dehydration is setting in or you just can’t shake it, walk into any ExperCARE location — no appointment needed. We can check for dehydration, rule out anything more serious, and get fluids or medication started fast. Find the nearest ExperCARE location at ExperCAREhealth.com

When to Get Medical Care

Most cases of norovirus clear up at home, but a few warning signs mean it’s time for professional care.

When should you go to urgent care?

• You or your child can’t keep any fluids down for more than 24 hours
• Signs of dehydration are setting in
• Symptoms last more than 3 days without improvement
• A fever above 102°F
• You need a same-day evaluation to confirm it’s norovirus and not something else

When should you go to the ER?

• Severe dehydration — confusion, fainting, or a rapid heartbeat
• Blood in vomit or stool
• Severe abdominal pain that doesn’t ease up
• Illness in an infant, an older adult, or someone with a chronic health condition, especially if symptoms are worsening

Keeping It From Spreading at Home

The single best defense is handwashing, but a few other habits go a long way too:

• Wash hands with soap and water for at least 20 seconds — hand sanitizer alone doesn’t reliably kill norovirus
• Disinfect high-touch surfaces with a bleach-based cleaner
• Wash contaminated laundry, sheets, and towels on the hottest setting
• Keep the person who’s sick away from food prep for at least 48 hours after symptoms stop
• Use a separate bathroom if possible, or disinfect thoroughly between uses

 

Frequently Asked Questions

Is a stomach bug the same thing as norovirus?

Often, yes. “Stomach bug” is an informal term, but norovirus is the single most common actual cause of short-term vomiting-and-diarrhea illness in the U.S.

What kills norovirus on surfaces?

Regular soap and most alcohol-based sanitizers don’t reliably kill it. A bleach-based disinfectant, used according to the label’s contact time, is the most effective option.

Can you get norovirus more than once?

Yes. Immunity is short-lived and there are many different strains, so having it once doesn’t protect you from getting it again.

How is norovirus different from food poisoning?

Bacterial food poisoning usually comes on faster after eating a specific contaminated food and typically doesn’t spread from person to person the way norovirus does.

Can norovirus spread through the air?

Not the way a cold or flu does, but vomiting can launch tiny virus particles into the air that get inhaled or land on nearby surfaces — so standing close to someone who’s vomiting can expose you even without direct contact.

Can over-the-counter medications like Imodium or Pepto-Bismol help?

Some adults find loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) helpful for easing diarrhea and nausea. Skip them if you have a fever or bloody stool, since that can signal something other than norovirus, and check with a doctor before giving either one to a child.

How is norovirus actually diagnosed?

Most of the time, it’s diagnosed based on symptoms alone — there’s no need for testing in a typical case. Stool testing can confirm norovirus specifically, but it’s mainly used during outbreak investigations rather than for individual patients.

Can pets catch norovirus from a sick family member?

Norovirus is generally species-specific, so the strain that makes people sick isn’t known to make dogs or cats ill. If a pet is vomiting or has diarrhea while someone in the house has norovirus, it’s more likely a coincidence or something unrelated — but it’s still smart to keep up thorough handwashing around pets during an outbreak at home.

 

The Bottom Line •       Most “stomach bugs” and “stomach flu” cases are actually norovirus — a highly contagious virus, not related to influenza. •       Symptoms start 12–48 hours after exposure and usually resolve in 1–3 days. •       You’re contagious before symptoms start and for up to 48 hours after they stop. •       It affects kids and adults alike — cruise ships, offices, and restaurants are common outbreak settings. •       Dehydration is the main risk to watch for; fluids, rest, and handwashing are your best tools.