A stomach bug typically lasts one to three days in most people, though symptoms can occasionally stretch to 14 days depending on the virus involved. The first day is usually the worst, with frequent vomiting and diarrhea, followed by a steady improvement over the next 24 to 48 hours.
Typical Duration by Virus Type
Not all stomach bugs run on the same clock. The two most common culprits, norovirus and rotavirus, have noticeably different timelines.
Norovirus, the virus behind most outbreaks in adults, moves fast. Symptoms appear within 12 to 48 hours of exposure and generally resolve in one to three days. It hits hard but burns out quickly. Rotavirus, which is more common in young children, takes about two days to show up after exposure and lasts longer: three to eight days of symptoms. That extended timeline is one reason rotavirus can be particularly rough on small kids, who are more vulnerable to dehydration from prolonged diarrhea.
What the Symptoms Look Like Day by Day
The pattern is fairly predictable. After one to three days of feeling fine (the incubation period, when the virus is multiplying but you don’t know it yet), symptoms arrive suddenly. The first day tends to be the most intense. You might throw up or have diarrhea many times, along with stomach cramps, nausea, and sometimes a low-grade fever or body aches.
The diarrhea is typically watery and not bloody. Bloody diarrhea usually signals something different, like a bacterial infection, and warrants a call to your doctor. By day two or three, the vomiting usually stops, appetite starts returning, and the diarrhea tapers off. Some people notice loose stools or mild fatigue for a few days after the worst has passed, but the acute misery is short-lived.
Stomach Bug vs. Food Poisoning
People often confuse the two because the symptoms overlap almost completely. The main difference is timing. Food poisoning tends to hit faster (sometimes within hours of eating contaminated food) and clears out faster, often within a day. A viral stomach bug generally lingers for about two days, sometimes longer. If your symptoms came on very suddenly after a specific meal and resolved within 24 hours, food poisoning is the more likely explanation.
You’re Still Contagious After You Feel Better
This is the part most people don’t realize. With norovirus, you can continue spreading the virus for two weeks or more after your symptoms have completely stopped. The CDC recommends staying home for at least 48 hours after your last episode of vomiting or diarrhea, but even after that window, careful hand hygiene matters.
Norovirus is also notoriously hard to kill on surfaces. Regular cleaning sprays won’t cut it. You need a bleach solution (5 to 25 tablespoons of household bleach per gallon of water) left on the surface for at least five minutes, or a disinfecting product specifically registered to work against norovirus. This is especially important for bathrooms, doorknobs, and any surface a sick person has touched.
Eating and Drinking During Recovery
Replacing lost fluids is the single most important thing you can do while sick. Frequent vomiting and diarrhea drain water and electrolytes quickly, so sip on clear fluids, broth, or oral rehydration solutions throughout the day, even if you can only manage small amounts at a time.
As for food, the old advice about sticking to bananas, rice, applesauce, and toast (the BRAT diet) has largely fallen out of favor. Research shows that following a restricted diet doesn’t actually help you recover faster. Once your appetite starts coming back, you can return to your normal diet even if you still have some diarrhea. For children, the same applies: give them whatever they normally eat as soon as they’re hungry again. Infants should continue getting breast milk or formula as usual.
Warning Signs in Children
Most stomach bugs are miserable but harmless. In young children, though, dehydration can become serious more quickly. Watch for signs that a child isn’t tolerating the illness well: no tears when crying, a dry mouth, no wet diapers for several hours, unusual drowsiness or irritability, or rapid breathing. Bloody or green-tinged vomit, a fever of 104°F or higher, or a child younger than six months with persistent symptoms all warrant prompt medical attention.
For adults, the same general rule applies. If diarrhea hasn’t improved at all after seven days, or if you can’t keep any fluids down for more than 24 hours, it’s worth getting checked out. Most people, though, will be through the worst of it well before that point.