Most stomach bugs clear up within 1 to 3 days. The worst of it, the intense vomiting and frequent diarrhea, typically peaks in the first 12 to 24 hours and then gradually winds down. But the specific timeline depends on what’s causing your illness, and some aftereffects can linger well beyond the main event.
Typical Timeline by Cause
Norovirus is the most common culprit behind what people call a “stomach bug.” Symptoms hit fast, usually 12 to 48 hours after exposure, and most people feel better within a day or two. It’s an intense but short illness: waves of nausea, vomiting, watery diarrhea, and sometimes a low fever that seem to come out of nowhere and then burn out quickly.
Rotavirus tends to last longer. Symptoms appear 1 to 3 days after exposure and can persist for 3 to 8 days. This is especially relevant for young children, who are the most commonly affected group. Adults who catch rotavirus usually have milder symptoms, but kids can be miserable for close to a week.
Bacterial gastroenteritis from sources like contaminated food can follow a different pattern entirely. These infections sometimes cause symptoms that drag on for a week or more, particularly if the diarrhea is severe. Bloody diarrhea at any point is a signal that something beyond a standard viral stomach bug is going on and warrants a call to your doctor.
What the First 72 Hours Look Like
The first day is almost always the hardest. Vomiting tends to be the dominant symptom early on, sometimes making it impossible to keep even small sips of water down. By the second day, vomiting usually slows or stops, but diarrhea often continues. Many people notice their appetite is completely absent during this window, which is normal.
By day two or three, most people start turning a corner. You might feel drained and your stomach may still feel “off,” but the active vomiting and urgent diarrhea taper off. Energy levels take a bit longer to bounce back. Feeling wiped out for a few days after your main symptoms resolve is common, especially if you got dehydrated during the worst of it.
When Gut Symptoms Linger Afterward
Even after the infection itself is gone, your digestive system can stay sensitive for days or even weeks. Loose stools, mild bloating, and a reduced tolerance for rich or fatty foods are all normal in the short term. Your gut lining took a hit, and it needs time to heal.
A smaller but significant number of people develop longer-lasting digestive issues. Roughly 7 to 33% of people who go through a bout of bacterial gastroenteritis develop symptoms resembling irritable bowel syndrome: cramping, irregular bowel habits, and bloating that persist for months. This is called post-infectious IBS, and it accounts for about 1 in 10 IBS cases overall. About half of those affected recover within six years, though many improve much sooner. If your digestion still feels off weeks after a stomach bug, that pattern is recognized and treatable.
How Long You Stay Contagious
Your contagious window extends beyond when you feel better. With norovirus, people can shed the virus in their stool for two weeks or more after symptoms resolve, though the highest risk of spreading it to others is during the illness itself and the first few days after recovery. This is why hand hygiene matters even when you feel fine again.
For returning to work or school, current CDC guidance focuses on practical thresholds: vomiting should have resolved overnight, and you should be able to keep food and liquids down in the morning. Diarrhea should have improved enough that you’re having no more than two extra bowel movements above your normal in a 24-hour period. Waiting at least 24 to 48 hours after your last episode of vomiting or diarrhea before going back to shared spaces is a reasonable standard that most workplaces and schools follow.
Signs That Need Medical Attention
Most stomach bugs are miserable but not dangerous. The main risk is dehydration, and certain signs tell you it’s becoming a problem. For adults, watch for an inability to keep any liquids down for 24 hours, very dark yellow urine or barely urinating at all, dizziness when standing, or vomiting and diarrhea that continue past the two-day mark.
For children and infants, the warning signs look different. A baby who hasn’t had a wet diaper in six hours, cries without tears, or has a sunken soft spot on the head needs immediate medical care. Older children who seem unusually lethargic, have a fever above 102°F, or show bloody diarrhea should also be seen promptly. Children dehydrate faster than adults, so the threshold for concern is lower.
A fever above 104°F in an adult, blood in vomit or stool at any age, or severe abdominal pain that goes beyond typical cramping are all reasons to seek care regardless of how long you’ve been sick.
Speeding Up Your Recovery
There’s no way to shorten a viral stomach bug once it starts. Antibiotics don’t work against viruses, and anti-diarrheal medications can actually slow your body’s effort to clear the infection. The most useful thing you can do is manage dehydration aggressively.
Small, frequent sips are more effective than gulping large amounts of fluid, especially when nausea is still active. Water is fine, but oral rehydration solutions or drinks with electrolytes replace the sodium and potassium you’re losing through vomiting and diarrhea. For children, pedialyte-style solutions are more effective than juice or sports drinks, which can worsen diarrhea due to their sugar content.
Once you can keep liquids down, start with bland, easy-to-digest foods: plain rice, toast, bananas, broth. Dairy, caffeine, alcohol, and high-fat foods are worth avoiding for a few days even after you feel mostly recovered, since your gut is still rebuilding its normal function. Most people are back to eating normally within a week of symptom onset.