Most stomach bugs last one to three days, though symptoms can stretch up to 14 days depending on the cause. Viral infections are the most common culprit and tend to resolve the fastest, while bacterial and parasitic infections can linger for a week or longer.
Viral Stomach Bugs: 1 to 8 Days
Viruses cause the vast majority of stomach bugs. Norovirus, the single most common cause, typically produces intense but short-lived symptoms. Vomiting and diarrhea usually last one to two days, though they can occasionally persist for up to 14 days. Rotavirus follows a similar pattern, with watery diarrhea and vomiting lasting three to eight days. In people with healthy immune systems, rotavirus is self-limited, meaning it resolves on its own without treatment.
The worst of a viral stomach bug usually hits within the first 24 to 48 hours. Vomiting often stops before diarrhea does, so you may feel like you’re improving even as loose stools continue for another day or two. That tail end of diarrhea is normal and doesn’t necessarily mean you’re getting worse.
Bacterial Infections: Up to a Week
Bacterial stomach bugs, often from contaminated food, generally take longer to arrive and longer to leave. Campylobacter, one of the most common bacterial causes, has an incubation period of two to five days. Once symptoms start, most people fully recover within seven days. Salmonella follows a roughly similar timeline, with diarrhea, cramps, and fever typically lasting four to seven days.
Bacterial infections are more likely to cause bloody diarrhea and higher fevers than viral ones. If your symptoms include blood in your stool or a fever that won’t come down, the cause may be bacterial rather than viral.
Parasitic Infections: Weeks to Months
Parasitic stomach bugs like Giardia are less common but last significantly longer. Symptoms usually begin one to two weeks after exposure and persist for two to six weeks. In some cases, people develop long-term symptoms that can last for years. Unlike viral bugs that burn through your system quickly, parasitic infections often require medication to fully clear. If your diarrhea, bloating, or nausea has dragged on for more than two weeks, a parasite is worth considering.
How Long You Stay Contagious
Here’s the part most people don’t realize: you remain contagious well after you feel better. With norovirus, you can still spread the virus for two weeks or more after symptoms resolve. The virus continues to shed in your stool for several weeks after recovery, even when you feel completely fine. That’s why hand hygiene matters long after the vomiting stops, especially if you’re around young children, elderly family members, or anyone with a weakened immune system.
During your illness and for at least two to three days after symptoms end, avoid preparing food for others and limit close contact when possible.
Eating During Recovery
The old advice about sticking to bland foods or fasting through a stomach bug doesn’t hold up. Research 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 diarrhea. For children, the same applies: give them what they usually eat as soon as they’re hungry again. Infants should continue receiving breast milk or formula as usual throughout the illness.
The priority during the acute phase is staying hydrated. Small, frequent sips of water, broth, or an oral rehydration solution work better than trying to gulp large amounts at once, which can trigger more vomiting.
Lingering Gut Issues After Recovery
Some people notice that their digestion doesn’t quite return to normal even after the infection clears. Bloating, cramping, and irregular bowel habits that persist for weeks or months after a stomach bug may be post-infectious irritable bowel syndrome, or PI-IBS. This condition can last for years. About half of PI-IBS cases resolve on their own within six to eight years after the original infection.
PI-IBS doesn’t mean the infection is still active. It’s your gut’s nervous system and bacterial balance recalibrating after the disruption. If you’re still dealing with digestive symptoms months after a stomach bug, it’s worth bringing up with your doctor, because treatments that help general IBS often help PI-IBS as well.
Signs of a More Serious Problem
Most stomach bugs are uncomfortable but harmless. Certain symptoms, however, signal that something more serious may be happening:
- In adults: vomiting or diarrhea lasting more than two days, inability to keep liquids down for 24 hours, blood in vomit or stool, severe stomach pain, or a fever above 104°F.
- In children: a fever of 102°F or higher, bloody diarrhea, unusual tiredness or irritability, or signs of dehydration like dry mouth, no tears when crying, or significantly less urination than normal.
- In infants: frequent vomiting, no wet diaper in six hours, a sunken soft spot on the head, or a dry mouth.
Dehydration is the main danger with any stomach bug, particularly for young children and older adults. Signs include excessive thirst, dark yellow urine or very little urine output, dizziness, and severe weakness.