Most stomach bugs last 1 to 3 days, though some can stretch to a week or longer depending on the cause. The vast majority of cases are viral, and symptoms typically peak within the first 24 to 48 hours before gradually improving.
Duration by Type of Infection
The most common culprit behind a stomach bug is norovirus, which causes symptoms lasting 1 to 3 days in most people. Symptoms appear within 1 to 2 days of exposure, hit hard and fast, and tend to resolve quickly. Rotavirus, which primarily affects young children, lasts longer: typically 3 to 8 days from the onset of symptoms, with an incubation period of 1 to 3 days before anything shows up.
Bacterial infections can follow a different timeline. Some are surprisingly short. Food poisoning caused by certain bacteria produces diarrhea and stomach cramps that resolve in less than 24 hours. Others, like salmonella or campylobacter infections, can drag on for several days to a week or more. In general, bacterial causes tend to produce more severe symptoms, including high fevers and bloody diarrhea, which can help distinguish them from a standard viral stomach bug.
What the Illness Feels Like Day by Day
Day one is usually the worst. Nausea, vomiting, watery diarrhea, and stomach cramps often come on suddenly, sometimes within hours of each other. Vomiting tends to be more prominent in the first 12 to 24 hours and often tapers off before the diarrhea does.
By day two, most people notice the vomiting has slowed or stopped, but diarrhea and fatigue usually linger. Low-grade fever and body aches are common during this window. By day three, the majority of people with norovirus feel noticeably better, though they may still feel wiped out and have looser-than-normal stools for another day or two. With rotavirus or a bacterial infection, this recovery phase can take several more days.
How Long You Stay Contagious
This is the part that surprises most people. Even after you feel completely better, you can still spread norovirus for 2 weeks or more. The CDC recommends staying home for at least 48 hours after your last symptoms resolve to reduce the risk of passing it on. During that time, careful handwashing with soap and water is essential, since alcohol-based hand sanitizers are less effective against norovirus.
Children, older adults, and people with weakened immune systems may shed the virus even longer. If someone in your household has been sick, disinfecting surfaces they’ve touched (especially bathrooms and kitchen areas) can help prevent the bug from spreading to everyone else.
Signs of Dehydration to Watch For
The biggest risk with any stomach bug isn’t the infection itself but the fluid loss from vomiting and diarrhea. In adults, warning signs of dehydration include very dark urine, dizziness when standing, dry mouth, and urinating much less than usual. In children, the key red flags are sunken eyes, no tears when crying, a dry mouth, reduced skin elasticity (when you gently pinch the skin, it’s slow to flatten back), and a rapid heart rate. The more of these signs present at once, the more likely significant dehydration is occurring.
Young children and older adults are at the highest risk. Norovirus alone causes roughly 109,000 hospitalizations per year in the United States, and by age 5, about 1 in 160 children will have been hospitalized for a related illness. Most of those hospitalizations are for dehydration, not the infection itself.
Eating and Drinking During Recovery
Staying hydrated is the single most important thing you can do while sick. Sip water, broth, or drinks with electrolytes frequently, even if you can only manage small amounts at a time. For infants, continue breast milk or formula as usual.
You may have heard of the BRAT diet (bananas, rice, applesauce, toast) or been told to avoid certain foods while recovering. Current guidance from the National Institute of Diabetes and Digestive and Kidney Diseases does not recommend fasting or following a restricted diet. Once your appetite starts to return, you can go back to eating your normal foods, even if diarrhea hasn’t fully resolved. Research shows that restricting your diet doesn’t speed up recovery.
When Symptoms Linger After the Bug Is Gone
Some people notice that their digestion doesn’t quite return to normal even after the infection has clearly passed. Bloating, cramping, and irregular bowel habits that persist for weeks or months after a stomach bug may be a condition called post-infectious irritable bowel syndrome. This isn’t a continuation of the original infection. It’s a disruption in how the gut functions, triggered by the inflammation the bug caused.
Post-infectious IBS is more common than most people realize, and it can last a long time. About half of cases resolve on their own within six to eight years, according to Cleveland Clinic. A formal diagnosis requires recurring abdominal pain at least once a week for three months, along with changes in stool frequency or consistency. If your stomach still feels “off” months after a stomach bug, this is a likely explanation and worth bringing up with a doctor.