A stomach virus typically lasts 1 to 3 days in most adults, though some infections can stretch closer to a week depending on the virus involved. The worst symptoms, vomiting and watery diarrhea, usually peak within the first 24 to 48 hours and then gradually taper off.
Duration by Virus Type
Several different viruses cause what people call the “stomach flu,” and each one follows a slightly different timeline.
Norovirus is the most common culprit in adults. Symptoms begin 12 to 48 hours after exposure and last 1 to 3 days. Most people recover completely without any treatment. Norovirus is also highly contagious, and you can continue shedding the virus in your stool for several weeks after you feel better.
Rotavirus is the leading cause of severe stomach illness in young children. Symptoms typically start about 2 days after exposure, and vomiting and watery diarrhea can last 3 to 8 days, which is notably longer than norovirus. Vaccination has dramatically reduced the number of severe cases in children, but unvaccinated kids tend to get hit harder and longer.
Astrovirus is less common and generally milder. Infections last 1 to 4 days in most people.
Enteric adenoviruses, another less common cause, can produce symptoms that linger for up to two weeks, making them the longest-lasting of the bunch.
What the Timeline Feels Like
The first 12 to 24 hours are usually the roughest. Vomiting often comes first and may be intense enough that you can’t keep anything down. Diarrhea, stomach cramps, and sometimes a low-grade fever follow shortly after. By day two, vomiting typically slows or stops, but diarrhea and fatigue can hang around for another day or two.
Even after the active symptoms clear, many people feel washed out for several more days. Your gut lining takes a beating during the infection, so mild bloating, reduced appetite, or loose stools for up to a week after recovery is normal. This lingering phase doesn’t mean you’re still sick; it just means your digestive system is still resetting.
Children and Infants Recover Differently
Kids, especially those under five, tend to have longer and more severe bouts of stomach illness. Rotavirus in particular can cause 3 to 8 days of watery diarrhea in young children, compared to the 1 to 3 days adults typically experience with norovirus. Children also lose fluids faster relative to their body size, which makes dehydration a bigger concern.
Infants are the most vulnerable. Signs to watch for include no wet diaper in six hours, a dry mouth, crying without tears, or a sunken soft spot on top of the head. Any of these warrants a call to your pediatrician right away. For older children, watch for unusual tiredness, irritability, bloody diarrhea, or a fever of 102°F or higher.
Staying Hydrated During the Worst of It
Dehydration is the main risk with any stomach virus, not the virus itself. The combination of vomiting and diarrhea drains fluids and electrolytes fast, and replacing them is the single most important thing you can do while you wait for the illness to pass.
If you’re vomiting frequently, don’t try to gulp large amounts of fluid at once. Start with small sips, about a teaspoon every five minutes, and gradually increase the amount as your stomach settles. Oral rehydration solutions (available at any pharmacy) work better than water alone because they replace lost sodium and glucose in the right proportions. Sports drinks are a reasonable backup for adults, though they contain more sugar than ideal.
For infants, continue breastfeeding or formula feeding as usual. Breast milk in particular provides both hydration and immune support. If an infant is vomiting frequently, offer smaller, more frequent feedings rather than stopping altogether.
Eating Again After a Stomach Virus
You don’t need to follow any special diet once your appetite starts returning. Current guidance from the National Institute of Diabetes and Digestive and Kidney Diseases is straightforward: go back to eating your normal diet as soon as you feel hungry, even if diarrhea hasn’t completely stopped. The old advice to stick exclusively to bland foods like bananas, rice, and toast for days isn’t necessary for most people.
That said, your gut may be temporarily more sensitive. Greasy, spicy, or very sugary foods can aggravate lingering diarrhea, so it makes sense to ease in with simpler meals for the first day or two. Dairy bothers some people temporarily because the infection can reduce your gut’s ability to break down lactose for a short period.
For children, the same principle applies: offer their normal foods as soon as they’re willing to eat. There’s no benefit to withholding food or restricting them to a limited diet.
When Symptoms Last Too Long
For adults, vomiting or diarrhea that continues beyond two days is worth a call to your doctor. Other red flags include being unable to keep liquids down for 24 hours, blood in your vomit or stool, severe stomach pain, or a fever above 104°F. These can signal a more serious infection, a bacterial cause rather than a viral one, or dehydration that may need medical support.
People with weakened immune systems, older adults, and those with chronic health conditions may experience longer illness and slower recovery. Viral shedding can also persist for weeks to months in immunocompromised individuals, which matters less for how you feel but more for how long you can spread the virus to others.
How Long You Stay Contagious
You’re most contagious while you have active symptoms, but the virus doesn’t leave your system the moment you feel better. Norovirus in particular can be shed in stool for several weeks after symptoms resolve. The practical takeaway: wash your hands thoroughly after using the bathroom for at least two weeks after recovery, and avoid preparing food for others during that window if possible. The virus spreads easily through contaminated hands, surfaces, and food.