Most stomach bugs last 1 to 3 days in adults and 3 to 7 days in children. The exact timeline depends on which virus is responsible, your age, and your overall health. The worst of it, especially the vomiting, often passes within the first 24 hours, but diarrhea and fatigue can linger for several days after that.
Duration by Virus Type
Not all stomach bugs run on the same clock. The virus behind your illness determines how long you’ll feel sick.
Norovirus is the most common cause of stomach bugs in adults and the culprit behind most outbreaks in places like cruise ships, restaurants, and offices. Symptoms appear 12 to 48 hours after exposure and typically last 1 to 3 days. It can strike at any time of year.
Rotavirus most often affects infants between 3 and 15 months old, though adults can catch it too. It tends to last longer, usually 3 to 8 days, with an incubation period of about 2 days. It peaks in fall and winter.
Adenovirus targets children under 2 and has the longest timeline of the common stomach viruses. Symptoms can stretch from 5 to 12 days and occur year-round.
How Symptoms Progress
A stomach bug typically hits fast. You might feel fine in the morning and be vomiting by the afternoon. The core symptoms are nausea, vomiting, diarrhea, and stomach pain, and during the worst stretch you can experience multiple episodes of vomiting or diarrhea in a single day.
Vomiting usually subsides before diarrhea does. Many people find that the intense nausea and vomiting settle within the first day or two, while loose stools continue for a few more days. Low energy and a general “washed out” feeling are common even after the main symptoms resolve.
Stomach Bug vs. Food Poisoning
If your symptoms came on very suddenly after a meal and passed within 24 hours, you may be dealing with food poisoning rather than a virus. Some types of bacterial food poisoning, like the kind caused by Clostridium perfringens, produce diarrhea and cramps that clear up in less than a day. Other bacterial infections can last several days or longer and may include blood in the stool or high fever, which are not typical of a standard viral stomach bug.
How Long You Stay Contagious
You’re most contagious while you have symptoms and for at least a few days after they stop. With norovirus specifically, viral particles continue to shed in your stool even after you feel better. This is why handwashing matters most in the days right after recovery, not just while you’re actively sick. Avoid preparing food for others during this window, and clean bathrooms thoroughly with a bleach-based product, since alcohol-based hand sanitizers are less effective against norovirus.
Dehydration Is the Main Risk
The stomach bug itself is rarely dangerous. The real threat is dehydration from losing fluids faster than you can replace them. This is especially true for young children, older adults, and anyone who can’t keep liquids down for several hours.
Signs of dehydration in adults include dark-colored urine, urinating less than usual, dry mouth, thirst, and headache. In infants and toddlers, watch for no wet diapers for 3 or more hours, no tears when crying, a dry mouth or cracked lips, and unusual sleepiness or irritability.
Sip small amounts of water, broth, or an oral rehydration solution frequently rather than trying to drink large amounts at once. For young children, offer whatever fluids they’ll accept in small, steady amounts.
When Symptoms Last Too Long
For adults, diarrhea lasting more than 2 days, a high fever, six or more loose stools per day, severe abdominal pain, or blood in the stool all warrant a call to your doctor. Frequent vomiting that prevents you from keeping any liquids down is also a reason to seek care.
The timeline is shorter for children. Diarrhea lasting more than a day, any fever in infants, vomiting for more than 24 hours, or signs of dehydration should prompt a call. For babies specifically, no wet diapers for 4 to 6 hours is a concerning sign.
Getting Back to Normal Eating
You don’t need to follow a strict bland diet once the worst passes. When your appetite returns, you can go back to eating your normal foods, even if you still have some diarrhea. The same applies to children: offer their regular diet as soon as they’re willing to eat again. Forcing bland foods when a child wants something else can actually slow recovery by reducing calorie intake.
One thing to be aware of: some people develop temporary difficulty digesting dairy after a stomach bug. This lactose sensitivity can last a month or more after the illness itself has resolved. If you notice bloating, gas, or loose stools after consuming milk or cheese in the weeks following a stomach bug, cutting back on dairy temporarily usually helps.