Most cases of stomach flu (viral gastroenteritis) last 1 to 3 days in adults, though some infections can stretch to 8 days depending on the virus involved. Children, especially infants and toddlers, tend to be sick longer than adults. The good news is that most people recover fully at home without any medical treatment.
How Long Each Virus Lasts
Two viruses cause the vast majority of stomach flu cases, and they follow different timelines.
Norovirus is the most common cause in adults. It hits fast, often within 12 to 48 hours of exposure, and most people feel better within a day or two after symptoms start. That quick turnaround is typical, but the 24 to 48 hours of active illness can be intense, with sudden vomiting, watery diarrhea, nausea, and stomach cramps.
Rotavirus is more common in infants and young children. Symptoms usually appear about 2 days after exposure and last 3 to 8 days. Vomiting tends to come first, followed by watery diarrhea that can persist for several days. Because young children lose fluids quickly and can’t always communicate how they feel, rotavirus tends to be more dangerous in this age group. A vaccine has dramatically reduced severe rotavirus cases in countries where it’s routinely given.
Day-by-Day Timeline
While every case is a little different, here’s what a typical norovirus infection looks like for an adult:
- Day 1: Symptoms appear suddenly. Vomiting and diarrhea are most frequent. You may also have a low fever, body aches, and fatigue. This is usually the worst day.
- Day 2: Vomiting often slows down or stops. Diarrhea may continue but becomes less frequent. Energy starts to return.
- Day 3 and beyond: Most people feel close to normal, though mild nausea, loose stools, or fatigue can linger for another day or two.
For rotavirus in children, the pattern is similar but stretched out. Vomiting is usually worst in the first 2 days, while diarrhea can continue for up to a week.
You’re Still Contagious After Feeling Better
This is the part most people don’t realize. Even after your symptoms clear up, you can still spread the virus for 2 to 3 days. During that window, you should avoid preparing food for others and limit close contact when possible. Frequent handwashing with soap and water is more effective than hand sanitizer against norovirus.
Your stool can actually continue shedding virus particles for several weeks after recovery, which is why thorough hand hygiene after using the bathroom matters long after you feel fine.
Dehydration Is the Real Danger
The stomach flu itself is rarely dangerous for otherwise healthy people. The risk comes from losing too much fluid through vomiting and diarrhea. Children, older adults, and people with weakened immune systems are most vulnerable.
Watch for these signs of dehydration:
- Dry mouth or dry eyes
- No tears when crying (in children)
- Less urine than normal, or fewer wet diapers in babies
- Skin that stays pinched when you gently pull it up, instead of bouncing back
- A fast heartbeat
If you notice these signs in yourself or your child, seek medical attention rather than trying to push through at home.
What to Eat and Drink During Recovery
Getting fluids back in is the single most important thing you can do, but timing matters. If you try to drink too much too soon, you’ll likely vomit it back up.
During the first few hours after vomiting stops, start with ice chips or a popsicle. Don’t try to chew or swallow anything substantial yet. Once ice chips stay down, move on to sipping clear liquids: water, apple juice, grape juice, or broth. Keep everything flat and clear. Avoid carbonated drinks.
After about 24 hours, try bland solid foods. The classic recommendation is the BRAT diet: bananas, rice, applesauce, and toast. Crackers, plain oatmeal, or plain grits work too. The goal is to give your gut something easy to process while it heals. Avoid dairy, fatty foods, caffeine, and alcohol until you’ve been eating normally for a day without problems.
For rehydration, oral rehydration solutions (available at any pharmacy) are more effective than sports drinks, sodas, or fruit juices, which tend to have too much sugar and can actually worsen diarrhea. For children with mild cases, diluted half-strength apple juice can work about as well as commercial rehydration solutions.
When Symptoms Drag On Too Long
If vomiting lasts more than 2 days in adults, or diarrhea continues beyond a week, something other than a typical stomach virus may be going on. Bacterial infections, parasites, or other conditions can mimic the stomach flu but require different treatment.
A fever above 104°F (40°C), bloody stool, or severe abdominal pain are also signals that the illness may not be a straightforward viral infection.
Even after a normal recovery, about 1 in 10 people who get a gut infection develop lingering digestive symptoms, a condition called post-infectious irritable bowel syndrome. This can include intermittent cramping, bloating, or changes in bowel habits that persist for weeks or months after the virus is gone. It’s not dangerous, but it can be frustrating if you expected everything to snap back to normal right away. These symptoms typically improve gradually on their own.