Most viral stomach bugs last 1 to 3 days, though some can drag on for up to 10 days depending on the virus involved and your overall health. The worst symptoms, vomiting and watery diarrhea, typically peak within the first 24 to 48 hours and then gradually improve. Here’s what to expect from start to finish.
Timeline by Virus Type
Not all stomach bugs follow the same clock. The two most common culprits have noticeably different timelines.
Norovirus is the leading cause of viral stomach illness in adults. Symptoms appear within 1 to 2 days of exposure and usually resolve within 1 to 3 days. It hits fast and hard, often starting with sudden, intense nausea followed by vomiting and diarrhea within hours. Most healthy adults feel significantly better by day 3.
Rotavirus is more common in young children, though adults can catch it too. Symptoms show up 1 to 3 days after exposure and tend to last longer, often 3 to 8 days. Children may experience a low-grade fever before the diarrhea begins, and the diarrhea itself can be more persistent than with norovirus.
Other viruses like adenovirus and astrovirus can also cause stomach illness. Adenovirus infections sometimes last a full week or longer, particularly in children. Regardless of the virus, if your symptoms haven’t started improving after 3 to 4 days, that’s worth paying attention to.
What Each Stage Feels Like
The first 12 to 24 hours are usually the roughest. Nausea and vomiting dominate early on, and you may not be able to keep anything down. Diarrhea often starts around the same time or shortly after the vomiting begins. Low-grade fever, body aches, and stomach cramps are common.
By day 2, vomiting usually slows or stops entirely. Diarrhea may continue but becomes less frequent. You’ll likely feel wiped out, which is partly from the infection itself and partly from fluid loss. This fatigue can linger for several days after the vomiting and diarrhea have resolved. Many people notice their appetite is suppressed for 3 to 5 days, even after the acute symptoms pass.
How Long You Stay Contagious
This is the part most people underestimate. You’re most contagious while you have active symptoms, but viral shedding continues after you feel better. With norovirus, you can spread the virus for at least 2 to 3 days after your symptoms resolve. Some studies have found viral shedding in stool samples for up to two weeks, though infectiousness drops significantly in the first few days after recovery.
Norovirus is also remarkably tough outside the body. It can survive on hard surfaces like countertops and doorknobs for 21 to 28 days at room temperature. This is why stomach bugs tear through households and workplaces so easily. Thorough handwashing with soap and water (not just hand sanitizer, which is less effective against norovirus) and disinfecting shared surfaces are the most reliable ways to stop the spread.
Staying Hydrated During Recovery
Dehydration is the main risk with a stomach bug, not the virus itself. When you’re losing fluids from both ends, replacing water alone isn’t enough. You also need electrolytes, specifically sodium and potassium, to help your body actually absorb the fluid.
Oral rehydration solutions (available at any pharmacy) are the most effective option. For children under 22 pounds, aim for about 2 to 4 ounces of rehydration solution after each episode of vomiting or diarrhea. For larger children and adults, 4 to 8 ounces per episode is a reasonable target. If you’re vomiting too frequently to keep anything down, try small, frequent sips every few minutes rather than drinking a full glass at once.
Signs of dehydration to watch for include dark yellow urine, urinating much less than usual, dry mouth, dizziness when standing, and in children, crying without tears or unusual sleepiness. Severe dehydration may require IV fluids, especially in very young children, older adults, and people with weakened immune systems.
What to Eat and When
The old advice to stick to bananas, rice, applesauce, and toast (the BRAT diet) is no longer the standard recommendation. While those foods are gentle on the stomach, the diet is too low in protein, calcium, fiber, and key vitamins to actually support recovery. The American Academy of Pediatrics specifically advises against following it for children, noting it can slow down gut recovery if used for more than 24 hours.
The current guidance is simpler: eat as tolerated. During the worst of it, bland foods are fine if that’s all you can manage. But as soon as you feel able to eat more, you should. Soft, easy-to-digest options like plain pasta, eggs, cooked vegetables, crackers, and lean chicken are all reasonable choices. Avoid greasy, spicy, or high-sugar foods until your stomach feels stable, as they can trigger more cramping or loose stools.
Most people can return to their normal diet within 2 to 4 days of symptom onset.
When Recovery Takes Longer Than Expected
Certain groups tend to have longer, more severe bouts. Children under 5 and adults over 65 often experience symptoms for a week or more. People with compromised immune systems, whether from medication, chronic illness, or other causes, may shed the virus and experience symptoms for weeks.
Antibiotics won’t help a viral stomach bug and can actually cause harm by disrupting your gut bacteria further. Anti-nausea medication is generally reserved for cases where vomiting is so severe that you can’t keep any fluids down. Over-the-counter anti-diarrheal medication can offer symptom relief for adults with watery diarrhea, but it’s not routinely necessary and is typically avoided in young children.
Some people notice their digestion feels “off” for a week or two after the infection clears. Temporary lactose sensitivity is common, so you may want to ease back into dairy. Loose stools that persist beyond two weeks, blood in your stool, a fever above 104°F, or an inability to keep fluids down for more than 24 hours are all signals that something beyond a routine stomach bug may be going on.