A stomach virus typically lasts 1 to 3 days in otherwise healthy adults. The total time you feel sick depends on which virus you caught, but most people are back to normal within a week at the outer edge. Here’s what to expect from the moment of exposure through full recovery.
Incubation: Before Symptoms Start
After you’re exposed to a stomach virus, there’s a gap before you feel anything. For norovirus, the most common cause of stomach bugs in adults, this incubation period is 12 to 48 hours. Rotavirus, which is more common in young children, takes about 2 days to produce symptoms. During this window you may already be contagious, even though you feel fine.
How Long Active Symptoms Last
Norovirus symptoms, including vomiting, watery diarrhea, nausea, and stomach cramps, generally resolve within 1 to 3 days. Rotavirus tends to drag on longer: vomiting and watery diarrhea can last 3 to 8 days, especially in children. Most adults with viral gastroenteritis feel significantly better by day two.
The worst of it usually hits in the first 12 to 24 hours. Vomiting often stops before diarrhea does, so you may have a day or two of loose stools after you’ve stopped throwing up. Low energy and a reduced appetite can linger for a few days beyond that, even after the main symptoms are gone.
Stomach Virus vs. Food Poisoning
If your symptoms came on very suddenly after a meal and cleared up quickly, food poisoning is the more likely explanation. Food poisoning tends to be brief, often resolving faster than a stomach virus. Viral gastroenteritis generally lingers for about two days, sometimes longer. The other key difference is timing: food poisoning typically strikes within hours of eating contaminated food, while a stomach virus builds over a day or two after exposure to an infected person or contaminated surface.
How Long You’re Contagious
This is where stomach viruses get tricky. You’re most contagious while you have symptoms and for the first few days after they stop. Norovirus can be shed in stool for weeks after you feel better, which is why handwashing matters long after you’re back on your feet.
The virus also survives on surfaces far longer than most people expect. Norovirus can persist on hard, dry surfaces at room temperature for up to 3 to 4 weeks. It can remain viable in carpets for up to 12 days even with regular vacuuming, and on electronics like keyboards and phones for at least 72 hours. This is a major reason stomach viruses spread so easily through households, schools, and offices.
When to Return to Work or School
CDC guidance for schools recommends that children (and staff) stay home until vomiting has resolved overnight and they can keep food and liquids down in the morning. Diarrhea should be improving, with bowel movements no more than two above the person’s normal frequency in a 24-hour period. Any fever should be gone for at least 24 hours without fever-reducing medication. These same benchmarks are reasonable for adults deciding whether to go back to work.
Eating During and After Recovery
While you’re actively vomiting, the priority is small sips of fluid rather than food. Once your appetite returns, you can go back to your normal diet even if you still have some diarrhea. There’s no need to restrict yourself to bland foods unless that’s what sounds appealing. For children, the same applies: offer their usual foods as soon as they’re willing to eat.
Signs of Dehydration to Watch For
The main danger of a stomach virus isn’t the virus itself but the fluid loss from vomiting and diarrhea. In healthy adults, this is uncomfortable but manageable. For infants, older adults, and people with weakened immune systems, dehydration can become serious enough to require IV fluids in a hospital.
In adults, warning signs include not being able to keep any liquids down for 24 hours, vomiting or diarrhea lasting more than two days, deep yellow urine or very little urine output, excessive thirst, dry mouth, dizziness, or severe weakness. Blood in vomit or stool, severe stomach pain, or a fever above 104°F also warrant prompt medical attention.
In infants, watch for no wet diaper in six hours, a sunken soft spot on the head, crying without tears, or a dry mouth. Children with a fever of 102°F or higher, bloody diarrhea, or unusual irritability should be seen by a doctor. Dehydration in small children can progress quickly since they have less fluid reserve to begin with.