Most stomach bugs last one to three days, though symptoms can stretch to seven days in some cases and occasionally linger up to 14 days. The exact timeline depends on which pathogen caused the infection, your age, and your overall health. Here’s what to expect from start to finish.
Typical Timeline by Cause
Viral gastroenteritis, the most common type of stomach bug, follows a fairly predictable pattern. Symptoms appear within one to three days after exposure and usually resolve within one to three days. Norovirus, the single most common culprit in adults, fits this window well. You’ll typically feel your worst during the first 24 hours, with vomiting and diarrhea peaking early before gradually tapering off.
Bacterial infections from sources like contaminated food can take a similar course but sometimes last longer. Most mild, uncomplicated cases of gastroenteritis, whether viral or bacterial, resolve within one to seven days. Bacterial causes are more likely to push toward the longer end of that range, and some produce bloody diarrhea or higher fevers that viral infections usually don’t.
Children, especially those under five, tend to have longer and more intense bouts. Their smaller bodies lose fluid faster, and their immune systems take more time to clear the infection. A stomach bug that knocks an adult down for two days might keep a toddler symptomatic for four or five.
What Each Phase Feels Like
The first sign is usually nausea, often hitting suddenly. Within hours, vomiting and watery diarrhea follow. Cramping, low-grade fever, and body aches are common companions. Most people describe the first 12 to 24 hours as the hardest stretch.
By day two or three, vomiting typically stops first while diarrhea hangs on a bit longer. You may feel wiped out and have little appetite even after the worst symptoms fade. This post-illness fatigue is normal and can last a few days beyond the active infection. Some people notice their digestion feels “off” for a week or more, with looser stools, mild bloating, or reduced tolerance for rich foods.
You’re Still Contagious After You Feel Better
One of the most important things to know is that your symptoms and your contagiousness don’t end at the same time. With norovirus, you can continue spreading the virus for two weeks or more after you feel completely recovered. The highest risk of transmission is during active symptoms and the first few days after recovery, but viral shedding continues well beyond that.
This means thorough handwashing remains critical even after you’re back on your feet. Norovirus is notoriously hardy. It survives on surfaces, resists alcohol-based hand sanitizers, and spreads in tiny amounts. Soap and water is your best defense during this contagious window.
Eating and Drinking During Recovery
Staying hydrated matters more than anything else you do during a stomach bug. Small, frequent sips of water, broth, or an oral rehydration solution work better than gulping large amounts, which can trigger more vomiting. For young children, the goal is roughly 10 mL per kilogram of body weight after each episode of diarrhea, on top of their regular fluid intake.
As for food, you may have heard you should stick to the BRAT diet (bananas, rice, applesauce, toast) or avoid eating until symptoms fully stop. Research doesn’t support either approach. Restricting your diet doesn’t shorten the illness or reduce symptoms. Once your appetite returns, you can go back to eating normally, even if diarrhea hasn’t completely resolved. For infants, breast milk or formula should continue as usual throughout the illness.
That said, a few things are worth avoiding while your gut recovers. Caffeine, high-fat foods, very sugary drinks, and dairy products can all worsen diarrhea in some people. Lactose intolerance, in particular, can develop temporarily after a stomach bug and persist for a month or longer. If milk or cheese seems to trigger cramping or loose stools after you’ve recovered, that’s why.
Signs It’s More Serious
Most stomach bugs are miserable but harmless. The main risk is dehydration, especially in young children, older adults, and people with chronic health conditions. Warning signs of severe dehydration include confusion or unusual drowsiness, a rapid heart rate, very dark urine or no urine output for many hours, and low blood pressure. In children, watch for a dry mouth, no tears when crying, or unusual irritability and lethargy. Severe dehydration is a medical emergency.
Symptoms that suggest something beyond a typical stomach bug include a fever above 102°F (39°C), bloody stool, severe abdominal pain that doesn’t come and go with cramping, and vomiting that prevents you from keeping any fluids down for more than 24 hours. These warrant medical evaluation, as they can point to a bacterial infection that needs treatment or a complication like significant fluid loss.
Why Some Stomach Bugs Last Longer
If your symptoms stretch past a week, several factors could be at play. Bacterial or parasitic infections generally take longer to clear than viral ones, and some require treatment to resolve. People with weakened immune systems, whether from medication, chronic illness, or age, often experience prolonged courses. And sometimes what feels like a lingering stomach bug is actually post-infectious irritation of the gut lining, which can cause loose stools and sensitivity to certain foods for weeks after the actual infection has cleared. This isn’t the bug itself lasting longer; it’s your digestive system recovering from the damage.