Most stomach bugs last 1 to 3 days, though symptoms can stretch up to 14 days depending on the cause. The typical viral stomach bug, especially norovirus (the most common culprit), clears within 1 to 3 days. Symptoms appear 1 to 3 days after you’re infected and usually hit fast: nausea, vomiting, watery diarrhea, stomach cramps, and sometimes a low-grade fever or body aches.
Duration by Cause
Not all stomach bugs run the same course. Norovirus, which causes the majority of cases in adults, resolves in 1 to 3 days. Rotavirus, more common in young children, follows a similar timeline but can drag on a bit longer. Bacterial causes tend to last longer than viral ones:
- Norovirus: 1 to 3 days
- Salmonella: 4 to 7 days
- Campylobacter: about 1 week
- Shigella: up to 1 week
- E. coli: 5 to 10 days
- Cryptosporidium (a parasite): 1 to 2 weeks
One clue that you’re dealing with something beyond a standard virus: bloody diarrhea. Viral stomach bugs almost always cause watery, non-bloody diarrhea. Blood in stool typically signals a bacterial infection that may need treatment.
How Symptoms Progress
Vomiting usually comes first and tends to be the shortest-lived symptom, often easing within 12 to 24 hours. Diarrhea follows and typically outlasts the vomiting by a day or two. Stomach cramps tend to come and go in waves between episodes and gradually fade as the diarrhea slows down. A low-grade fever and muscle aches, if they show up at all, usually resolve within the first day.
The worst of it is generally compressed into the first 24 hours. By day two or three, most people feel significantly better even if occasional loose stools continue.
How Long You’re Contagious
This is the part that catches people off guard. You can spread norovirus for two weeks or more after you feel completely better. The virus continues shedding in stool long after symptoms stop, which is why stomach bugs tear through households and workplaces so effectively.
The CDC recommends waiting at least 48 hours after your last symptoms before preparing food, returning to a restaurant or food service job, or caring for others. This is especially important in settings like daycare centers, schools, and long-term care facilities. Thorough handwashing with soap and water (not just hand sanitizer) is the most effective way to reduce transmission during this window.
Eating and Drinking During Recovery
The most important thing during a stomach bug is staying hydrated. Small, frequent sips of water, broth, or an oral rehydration solution work better than trying to gulp large amounts at once, which can trigger more vomiting.
As for food, the current guidance may surprise you: research shows that following a restricted diet doesn’t help treat viral gastroenteritis. You don’t need to fast, and you don’t need to stick to the old BRAT diet (bananas, rice, applesauce, toast). When your appetite returns, go back to eating your normal diet, even if you still have some diarrhea. For infants, continue breast milk or formula as usual.
That said, a few things can make lingering diarrhea worse while your gut recovers. Caffeine, high-fat foods like fried food or pizza, very sugary drinks, and dairy products are the main offenders. Dairy is worth particular attention: some people have trouble digesting lactose for a month or more after a stomach bug, even if they had no issues with milk before. If dairy seems to trigger symptoms after you’ve recovered, give it a few weeks and try again.
Dehydration Warning Signs in Children
Young children and infants are the most vulnerable to dehydration from a stomach bug because they lose fluids faster relative to their body size. Signs to watch for include dry lips and tongue, no tears when crying, sunken eyes, and dry or wrinkled-looking skin. In infants, a sunken soft spot on the head is a red flag. If a toddler has no wet diapers for eight hours, or an infant has fewer than six wet diapers per day, that signals dehydration that needs medical attention promptly.
When Gut Problems Linger for Weeks or Months
Sometimes the infection clears but your digestive system doesn’t fully bounce back. A condition called post-infectious IBS can develop after a stomach bug, causing ongoing cramping, bloating, diarrhea, or constipation that persists well beyond the original illness. About half of people who develop this condition see it resolve on its own within six to eight years, though for many it improves much sooner.
If you’re still experiencing irregular bowel habits, cramping, or unusual sensitivity to certain foods several weeks after a stomach bug, that pattern is worth discussing with a doctor. It doesn’t mean something is seriously wrong, but it does mean your gut may need more time and possibly some dietary adjustments to fully reset.