Vomiting from a stomach bug typically lasts 1 to 3 days. Most people feel the worst during the first 12 to 24 hours, with vomiting tapering off before diarrhea and fatigue do. The total illness, including lingering symptoms like loose stools and low energy, can stretch a bit longer, but the intense vomiting phase is usually the shortest part.
The Typical Timeline
A stomach bug, or viral gastroenteritis, follows a fairly predictable pattern. Symptoms begin 12 to 48 hours after you’re exposed to the virus. Vomiting and nausea usually hit first, often alongside stomach cramps, and tend to be the most intense in the first day. By day two or three, the vomiting has usually stopped, though diarrhea often lingers a day or two beyond that.
Norovirus is the most common cause of stomach bugs in adults, and it accounts for the classic “24-hour bug” experience many people describe. Some people recover in under 24 hours, while others take closer to 72 hours. Children, older adults, and people with weakened immune systems tend to be on the longer end of that range.
Stomach Bug vs. Food Poisoning
If vomiting started within two to six hours of eating something questionable, you’re more likely dealing with food poisoning than a stomach bug. Food poisoning comes on fast and tends to resolve faster, sometimes within a few hours. A stomach bug takes longer to show up (that 24 to 48 hour incubation window) and generally lingers for about two days.
The distinction matters because food poisoning usually doesn’t spread from person to person, while a stomach bug is highly contagious. If other people in your household start getting sick a day or two after you do, that points toward a virus rather than something you ate.
What Recovery Actually Looks Like
The vomiting phase is miserable but mercifully short. Here’s what to expect as you move through it:
- Hours 0 to 12: Nausea and vomiting ramp up quickly. You may vomit multiple times per hour at the peak. Diarrhea, body aches, and sometimes a low fever show up around the same time.
- Hours 12 to 24: Vomiting usually starts to slow. You might go longer stretches without an episode, though nausea can persist.
- Days 2 to 3: Vomiting stops for most people. Diarrhea and fatigue often continue. Your appetite gradually returns.
- Days 4 to 7: Energy levels normalize. Some people experience loose stools or mild stomach sensitivity for up to a week.
Staying Hydrated While You’re Sick
Dehydration is the main risk with a stomach bug, especially when vomiting makes it hard to keep anything down. The goal during the first 24 hours is small, frequent sips rather than gulping a full glass of water. Aim for at least one ounce (about two tablespoons) of fluid per hour. Oral rehydration solutions work well because they replace both water and the electrolytes you’re losing.
Don’t wait until the vomiting stops entirely to start sipping fluids. Even if you throw some of it back up, your body absorbs a portion. Small amounts every few minutes are easier on your stomach than large drinks spaced far apart.
When to Eat Again
You don’t need to follow a special diet or stick to bland foods like bananas and toast. Research shows that restricted diets don’t help you recover faster from a stomach bug. Once your appetite returns, you can go back to eating normally, even if you still have some diarrhea.
That said, a few things are worth avoiding in the first few days of recovery. Caffeine, high-fat foods, and very sugary drinks can make diarrhea worse. Dairy is another one to be cautious with. Some people have trouble digesting lactose for up to a month after a stomach bug, so if milk or cheese seems to upset your stomach during recovery, give it some time.
For children, the same principle applies: offer their regular foods as soon as they’re interested in eating. Infants should continue breast milk or formula throughout the illness.
Signs That Something More Serious Is Happening
Most stomach bugs resolve on their own, but dehydration can become dangerous, particularly in young children and older adults. Watch for these warning signs:
In adults: dark-colored urine, urinating much less than usual, extreme thirst, dizziness, confusion, or skin that stays “tented” when you pinch it instead of flattening back quickly.
In young children: no wet diapers for three hours or more, no tears when crying, a dry mouth, sunken eyes, unusual sleepiness or irritability, or rapid heart rate.
If you can’t keep any fluids down for more than 24 hours, have a fever of 102°F or higher, or notice blood in your stool, those are signs that warrant medical attention. Persistent vomiting beyond three days also falls outside the normal range for a typical stomach bug and is worth getting checked out.
How Long You’re Contagious
Even after the vomiting stops, you can still spread the virus. People with norovirus remain contagious for at least two to three days after symptoms resolve. Some people shed the virus in their stool for even longer. Thorough handwashing with soap and water is the most effective way to prevent spreading it to others during this window. Alcohol-based hand sanitizers are less effective against norovirus than regular soap.