A stomach bug typically lasts 1 to 3 days, though some cases stretch closer to a week depending on the virus involved. Most people start feeling noticeably better within 48 hours of their first symptoms. Here’s what to expect from start to finish and what can affect your personal timeline.
Typical Duration by Cause
The most common culprit behind stomach bugs is norovirus, which causes vomiting, diarrhea, and stomach pain starting 12 to 48 hours after exposure. Symptoms usually resolve within 1 to 3 days. For most healthy adults, the worst of it passes in about two days.
Rotavirus, which is more common in young children, tends to last longer. Vomiting and watery diarrhea from rotavirus can persist for 3 to 8 days. Adults who catch rotavirus generally have milder symptoms than children, but the timeline can still be longer than a typical norovirus bout.
Food poisoning, which people often confuse with a stomach bug, tends to be shorter. It comes on fast and clears out faster, sometimes within a single day. The key difference: food poisoning is caused by bacteria or toxins in contaminated food, while a stomach bug is a viral infection that spreads person to person.
What the Timeline Looks Like
The first 12 to 24 hours are usually the roughest. Vomiting often hits first, sometimes followed by diarrhea within a few hours. You may also have a low fever, body aches, and stomach cramps. During this phase, keeping anything down can feel impossible.
By day two, vomiting typically slows or stops. Diarrhea often lingers a bit longer, sometimes continuing for a day or two after the vomiting ends. Energy levels start to climb back, though you’ll likely still feel washed out. By day three or four, most people are eating normally again and feeling close to baseline, even if their digestion isn’t 100 percent yet.
You’re Still Contagious After You Feel Better
This catches many people off guard. Even after your symptoms are completely gone, you can still spread norovirus for two weeks or more. The virus continues shedding in your stool long after the diarrhea stops. This is why stomach bugs tear through households, daycares, and cruise ships so effectively.
Thorough handwashing with soap and water is the most effective way to reduce transmission during this window. Alcohol-based hand sanitizers are less effective against norovirus than they are against many other germs.
When You Can Go Back to Work or School
CDC guidelines for schools recommend that children stay home until vomiting has resolved overnight and they can hold down food and liquids the next morning. For diarrhea, the standard is that it has improved enough that the child is having no more than two bowel movements above their normal number in a 24-hour period. The same general principle applies to adults returning to work: wait until vomiting has stopped and diarrhea is under control, keeping in mind that you’re still contagious even after you feel fine.
Eating and Drinking During Recovery
Dehydration is the main risk with a stomach bug, not the infection itself. If you’re vomiting frequently, try sipping small amounts of clear liquids rather than drinking a full glass at once. Water, broth, and oral rehydration solutions all work. Small, frequent sips are far more likely to stay down than large gulps.
Once your appetite starts returning, you can go back to eating your normal diet. Research shows that following a restricted diet (like the old “BRAT diet” of bananas, rice, applesauce, and toast) doesn’t actually help you recover faster. Eat what sounds good and what you can tolerate. If you still have some diarrhea, that’s normal and doesn’t mean you need to avoid solid food.
Signs That Something More Serious Is Happening
Most stomach bugs are miserable but harmless. However, adults should get medical attention if they experience diarrhea lasting more than two days, a high fever, six or more loose stools in a day, severe abdominal pain, or stools that are black, bloody, or contain pus. Any signs of dehydration also warrant a call: dark urine, urinating much less than usual, extreme thirst, dizziness, or feeling faint.
For infants and young children, the thresholds are lower. Seek help if a child has diarrhea lasting more than one day, any fever in infants, frequent vomiting, signs of low energy or irritability, or no wet diapers for three hours or more. Children who were born prematurely or have other health conditions need earlier attention. Older adults, pregnant women, and anyone with a weakened immune system should also be evaluated sooner rather than later.
When Gut Symptoms Linger for Weeks or Months
About 1 in 10 people who get a gut infection develop a condition called post-infectious IBS, where bloating, cramping, or irregular bowel habits continue long after the virus is gone. This isn’t a sign that you’re still sick with the original bug. Instead, the infection temporarily disrupts the normal function of your gut, and it takes time for everything to recalibrate. About half of these cases resolve on their own within six to eight years, though many people improve much sooner. If your digestion still feels off weeks after a stomach bug, that’s a recognized pattern and worth mentioning to your doctor.