Most cases of stomach flu (viral gastroenteritis) last 1 to 3 days. Norovirus, the most common cause, typically resolves within that window, though some viral strains can stretch symptoms out to a full week or longer. How quickly you recover depends on which virus you caught, your age, and how well you stay hydrated.
Duration by Virus Type
Norovirus causes the majority of stomach flu cases in adults and older children. Symptoms, including vomiting, diarrhea, and stomach cramps, appear 12 to 48 hours after exposure and usually clear up within 1 to 3 days. Most people feel significantly better by day two.
Rotavirus tends to hit harder and longer, especially in young children. Symptoms can last anywhere from 3 to 8 days, and the vomiting and watery diarrhea are often more severe. Rotavirus vaccination has dramatically reduced cases in children, but unvaccinated kids and adults in close contact with them can still catch it.
What the Timeline Looks Like
The illness follows a fairly predictable arc. After the 12 to 48 hour incubation period, vomiting usually comes first, often hitting suddenly. Diarrhea follows and can persist a day or two after the vomiting stops. Low-grade fever, body aches, and fatigue are common throughout. Most people notice the worst symptoms in the first 24 hours, with gradual improvement after that.
Even after you feel better, your digestive system needs time to fully recover. Your appetite may be off for several days, and loose stools can linger for a few days beyond the acute phase.
Staying Hydrated During Recovery
Dehydration is the primary danger of stomach flu, not the virus itself. Every episode of vomiting or watery diarrhea pulls fluid and electrolytes out of your body faster than you might realize.
The key is replacing fluids in small, frequent amounts rather than gulping large quantities at once. If you’re vomiting frequently, start with about a teaspoon of fluid at a time and gradually increase the amount as your stomach tolerates it. For children under about 22 pounds, aim for 2 to 4 ounces of an oral rehydration solution after each episode of vomiting or diarrhea. Older children and adults should aim for 4 to 8 ounces per episode. Water alone isn’t ideal because it doesn’t replace the sodium and potassium you’re losing. Oral rehydration solutions, broth, and diluted sports drinks are better options.
Watch for signs that dehydration is becoming serious: dark urine or very little urine output, dizziness when standing, dry mouth, or unusual sleepiness. In children, look for fewer wet diapers, no tears when crying, or unusual irritability. Seek medical care if someone can’t keep any fluids down, has had diarrhea for more than 24 hours, has bloody or black stool, or runs a fever above 102°F.
What to Eat (and What to Skip)
You’ve probably heard of the BRAT diet (bananas, rice, applesauce, toast) as the go-to stomach flu food plan. It’s not wrong exactly, but it’s unnecessarily restrictive. The CDC notes that this approach can provide suboptimal nutrition during a time when your gut actually needs fuel to heal. Withholding food for more than 24 hours is counterproductive. Eating earlier in the illness reduces its duration and helps your intestinal lining recover faster.
Start with whatever bland, easy-to-digest foods sound tolerable. Plain crackers, boiled potatoes, chicken soup, and oatmeal are all fine choices. Avoid greasy, spicy, or very sugary foods until your stomach settles. Dairy can be tricky for some people during recovery since the infection can temporarily reduce your ability to digest lactose.
How Long You’re Contagious
This is where stomach flu gets tricky. You’re most contagious while you have symptoms and for at least 48 hours after they stop. With norovirus specifically, viral shedding can continue for up to two weeks after the illness begins, even though you feel fine.
Public health guidelines are clear on the 48-hour rule: don’t return to work, school, or childcare until you’ve been symptom-free (no vomiting or diarrhea) for a full two days. This is especially important for anyone who handles food, works in healthcare, or cares for young children or elderly adults. Thorough handwashing with soap and water matters more than hand sanitizer here, since alcohol-based sanitizers are less effective against norovirus.
When Recovery Takes Longer Than Expected
If your symptoms haven’t improved after 3 to 4 days, or if they seem to be getting worse rather than better, something else may be going on. Bacterial infections from contaminated food can mimic stomach flu but sometimes require different treatment. Persistent high fever, bloody diarrhea, or severe abdominal pain all warrant a call to your doctor.
There’s also a lesser-known aftermath of stomach flu worth knowing about. Research estimates that 3% to 36% of people who go through a bout of gastroenteritis develop lingering digestive symptoms afterward, a condition called post-infectious irritable bowel syndrome. One study found that nearly 24% of people who had viral gastroenteritis reported IBS-like symptoms, including bloating, cramping, and altered bowel habits, three months later. These symptoms usually improve over time, but if your digestion still feels off weeks after the flu is gone, that’s a recognized pattern rather than something you’re imagining.