Diarrhea from a stomach bug typically lasts 1 to 3 days for most viral infections, though some cases can stretch to 7 days or occasionally longer depending on the cause. The overall illness, including nausea and body aches, usually resolves within that same window, but your bowel movements may take a few extra days to fully return to normal even after you start feeling better.
Viral Stomach Bugs: The Most Common Cause
Norovirus is the most frequent culprit behind stomach bugs in adults. Symptoms hit fast, often within 12 to 48 hours of exposure, and the worst of it, including watery diarrhea, vomiting, and stomach cramps, usually passes within 1 to 3 days. Rotavirus, which is more common in young children, tends to last a bit longer, with diarrhea persisting for 3 to 8 days. Children who haven’t been vaccinated against rotavirus can have especially prolonged bouts.
The reason diarrhea happens in the first place is that the virus disrupts the lining of your intestines. Infected cells lose their ability to absorb fluid normally, and in some cases the gut actively secretes extra fluid into the intestine. The result is loose, watery stool. Your intestinal lining regenerates relatively quickly, which is why most people bounce back within a few days, but the gut can remain slightly irritated even after the virus is cleared.
Bacterial Infections Take Longer
Not every stomach bug is viral. Bacterial infections from contaminated food or water can cause similar symptoms but often drag on longer. Campylobacter, one of the most common bacterial causes of food poisoning, produces symptoms that start 2 to 5 days after exposure and usually resolve within 7 days. Salmonella infections follow a similar pattern, with diarrhea lasting 4 to 7 days in most cases. Some strains of E. coli can cause illness lasting a week or more.
A key difference: bacterial stomach bugs are more likely to cause bloody diarrhea, higher fevers, and more intense cramping than viral ones. If your diarrhea contains blood or you develop a fever above 102°F (39°C), that’s a signal the cause may be bacterial rather than a standard stomach virus.
Why Some People Recover Slower
Several factors influence whether you’re on the shorter or longer end of the recovery timeline. Young children, older adults, and people with weakened immune systems tend to have longer episodes because their bodies are slower to fight off the infection and repair the intestinal lining. Dehydration also plays a role. If you’re not replacing fluids adequately, your gut recovery slows and symptoms can feel worse and last longer.
It’s also common to have a few days of loose (but not watery) stools after the acute illness has passed. This post-infection phase happens because your gut flora and intestinal lining are still recovering. Some people notice mild digestive sensitivity for 1 to 2 weeks, particularly with dairy, fatty foods, or high-fiber meals. This is temporary and doesn’t mean the infection is still active.
You’re Contagious Longer Than You Think
Feeling better doesn’t mean you’ve stopped spreading the virus. The CDC notes that norovirus can be shed for 2 weeks or more after symptoms resolve. This is why stomach bugs tear through households, daycare centers, and cruise ships so effectively. Thorough handwashing with soap and water (not just hand sanitizer, which is less effective against norovirus) is critical during this window.
For returning to work or school, CDC guidance suggests waiting until vomiting has resolved overnight and you can keep food down, and until diarrhea has improved to no more than two extra bowel movements above your normal in a 24-hour period. For practical purposes, most workplaces and schools expect at least 24 to 48 hours free of vomiting and severe diarrhea before you come back.
What to Eat During Recovery
The old advice to stick to bananas, rice, applesauce, and toast (the BRAT diet) is no longer recommended by most experts. Research from the National Institute of Diabetes and Digestive and Kidney Diseases shows that following a restricted diet does not help treat viral gastroenteritis. Once your appetite returns, you can go back to eating your normal diet, even if you still have some diarrhea. The same applies to children: give them their usual foods as soon as they’re willing to eat.
The priority during a stomach bug is hydration, not food restriction. Water, broth, and oral rehydration solutions replace the fluid and electrolytes you’re losing. Small, frequent sips work better than gulping large amounts, especially if nausea is still present. Avoid alcohol and caffeinated drinks, which can worsen dehydration.
Signs the Illness Needs Medical Attention
Most stomach bugs resolve on their own, but certain symptoms warrant a call to your doctor or a trip to urgent care. Watch for signs of dehydration: excessive thirst, dark-colored urine, infrequent urination, dry mouth, or dizziness when standing. Vomiting that lasts more than two days in adults, more than 24 hours in children under 2, or more than 12 hours in infants is another threshold that warrants medical evaluation.
Seek more urgent attention if you notice blood in your stool, severe abdominal pain or cramping, a high fever with a stiff neck, confusion, or vomit that contains blood or looks like coffee grounds. These can signal a more serious infection, complications from dehydration, or a condition that isn’t a stomach bug at all.