Most stomach viruses last 1 to 3 days, with the worst symptoms typically hitting within the first 24 hours and gradually easing after that. However, the specific virus you’ve caught matters. Norovirus, the most common cause of stomach flu in adults, tends to resolve faster than rotavirus or other viral infections, which can drag on for a week or more.
Timeline by Virus Type
Norovirus is responsible for the majority of stomach flu cases in adults, and it moves fast. Symptoms usually appear 12 to 48 hours after exposure and last 1 to 3 days. You’ll likely feel the worst on day one, with intense nausea, vomiting, and watery diarrhea, then notice gradual improvement by day two or three.
Rotavirus hits harder in young children and tends to last longer, with outbreaks averaging around 11 days in group settings like daycares. Individual illness episodes typically run 3 to 8 days. Sapovirus, a less common cause, follows a similar pattern with outbreaks lasting about 9 days on average. Adenovirus is the slowest of the group, with outbreaks stretching to a median of 19 days, partly because the virus itself causes a longer-lasting infection in each person it hits.
If your symptoms persist beyond 3 days as an adult, or beyond a week in a child, the virus may not be a typical norovirus. Longer-lasting cases are more common with rotavirus and adenovirus, and they carry a higher risk of dehydration simply because the body loses fluids over a longer stretch.
What Each Day Typically Looks Like
Day one is usually the roughest. Vomiting tends to come first, sometimes before diarrhea even starts. Many people can’t keep any food or liquids down during the first 6 to 12 hours. You may also have a low-grade fever, body aches, and cramping.
By day two, vomiting usually slows or stops, though diarrhea often continues. Your appetite may start to return in small waves. Day three, for most norovirus cases, brings a noticeable turn. Diarrhea becomes less frequent, energy starts creeping back, and you can tolerate more food. That said, your stomach may feel “off” for several more days even after the active infection clears. Loose stools and mild nausea can linger for up to a week as your gut lining repairs itself.
How Long You’re Contagious
This is the part most people underestimate. You’re contagious from the moment symptoms appear, but you can still spread norovirus for 2 weeks or more after you feel completely better. The virus continues shedding in stool long after diarrhea and vomiting stop, which is why hand hygiene matters well into recovery.
For practical purposes, the CDC recommends that children stay home from school until vomiting has resolved overnight and they can hold down food and liquids the next morning. Diarrhea should have improved enough that bowel movements are no more than two above the child’s normal frequency in a 24-hour period. Adults returning to work should follow the same general rule: wait at least 24 to 48 hours after your last episode of vomiting or diarrhea before going back to shared spaces, especially if you work with food or in healthcare.
Staying Hydrated During Recovery
Dehydration is the real danger with a stomach virus, not the virus itself. The key is replacing fluids in small, frequent amounts rather than gulping large quantities that your stomach will reject. Start with a teaspoon or two of liquid every few minutes. If that stays down, gradually increase the amount.
For children under 22 pounds (10 kg), aim for about 2 to 4 ounces of an oral rehydration solution after each episode of vomiting or diarrhea. Children over that weight need 4 to 8 ounces per episode. Adults can use oral rehydration solutions, diluted sports drinks, or broth. Water alone isn’t ideal because it doesn’t replace the sodium and potassium you’re losing.
If you or your child shows signs of moderate dehydration (dark yellow urine, dry mouth, dizziness, unusual thirst), the goal is roughly 1.5 to 3 ounces of rehydration fluid per pound of body weight over 2 to 4 hours. That sounds like a lot, but sipped slowly, most people can tolerate it even with ongoing nausea.
What to Eat as Symptoms Ease
The old advice to stick strictly to bananas, rice, applesauce, and toast (the BRAT diet) is outdated. There are no studies showing it works better than simply eating bland, easy-to-digest foods as tolerated. It’s fine for the first day or two, but restricting yourself to only those four foods can actually slow recovery because they lack the protein and nutrients your body needs to heal.
Once you can keep liquids down reliably, try adding brothy soups, oatmeal, boiled potatoes, crackers, or unsweetened dry cereal. As your stomach settles further, move toward cooked vegetables like butternut squash, carrots, or sweet potatoes (without the skin), along with avocado, eggs, skinless chicken or turkey, and fish. These provide protein while still being gentle on your digestive system. Avoid dairy, caffeine, alcohol, and fatty or heavily spiced food until you’ve had at least a full day of normal bowel movements.
Warning Signs That Need Medical Attention
Most stomach viruses resolve on their own, but certain symptoms signal that something more serious is happening. For adults, the red flags are: inability to keep any liquids down for 24 hours, vomiting or diarrhea lasting more than two days, vomiting blood, blood in your stool, severe stomach pain, or a fever above 104°F. Signs of significant dehydration (extreme thirst, very little or no urine output, dizziness, or severe weakness) also warrant a call to your doctor.
Children need closer monitoring because they dehydrate faster. Contact your child’s doctor if they have a fever above 102°F, seem unusually tired or irritable, have bloody diarrhea, or show signs of dehydration like a dry mouth, crying without tears, or reduced urination. For infants, frequent vomiting, no wet diaper in six hours, a sunken soft spot on the head, or severe diarrhea all require prompt medical evaluation.