The stomach flu (viral gastroenteritis) runs its course in one to three days for most adults, and the best thing you can do is focus on staying hydrated while your body fights off the virus. There’s no antibiotic or antiviral that treats it. But the right approach to fluids, food, and rest can make a real difference in how miserable you feel and how quickly you bounce back.
How Long It Lasts
The timeline depends on which virus you’ve picked up. Norovirus, the most common cause in adults, typically lasts one to three days. Rotavirus, which hits young children hardest, can stretch to three to seven days. Adenovirus infections in toddlers sometimes drag on for five to twelve days. Symptoms usually begin one to two days after exposure, so you may not connect the illness to the meal or contact that caused it.
Most people feel worst during the first 24 hours, when vomiting is frequent and diarrhea is at its peak. By day two or three, the nausea fades and energy slowly returns, though loose stools can linger a few days beyond that.
Fluids Are the Priority
Dehydration is the main danger with the stomach flu, not the virus itself. Every bout of vomiting or diarrhea pulls water and electrolytes out of your body, and replacing both is more important than eating.
The most effective approach is an oral rehydration solution (ORS), available at most pharmacies and grocery stores. These drinks are formulated with a specific balance of sodium and glucose that helps your gut absorb fluid far more efficiently than water alone. The World Health Organization’s recommended formula contains equal parts sodium and glucose at 75 milliequivalents per liter each. Commercial versions sold in stores use a slightly different ratio but still work well.
Sports drinks, sodas, and fruit juices are not good substitutes. They contain too much sugar and too little sodium, and the excess sugar can actually pull more water into your intestines and worsen diarrhea. If ORS isn’t available, small sips of broth or diluted juice are better than nothing, but grab the real thing when you can.
Take small, frequent sips rather than gulping large amounts, especially if you’re still vomiting. A few tablespoons every five to ten minutes is easier to keep down than a full glass.
What and When to Eat
You may have heard of the BRAT diet (bananas, rice, applesauce, toast), but current guidance has moved away from restricted diets. Research shows that limiting yourself to bland foods doesn’t speed recovery from viral gastroenteritis. Once your appetite starts to return, you can go back to eating your normal diet, even if diarrhea hasn’t fully stopped.
That said, your body will tell you what it can handle. Most people naturally gravitate toward simple foods like crackers, plain rice, or soup during the first day or two because their stomach simply won’t tolerate anything heavier. That’s fine. The key point is that you don’t need to force a restricted diet. When you feel hungry for regular food, eat it. For children, the same advice applies: offer what they normally eat as soon as they show interest.
A few things are worth avoiding while your gut is irritated: very fatty or greasy food, caffeine, alcohol, and dairy products if they seem to make symptoms worse. These can all increase nausea or loosen stools in an already sensitive digestive system.
Over-the-Counter Medications
Adults can use anti-diarrheal medications like loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) to reduce the frequency of diarrhea. These won’t shorten the illness, but they can make it more manageable, especially if you need to function during the day.
There are important exceptions. Do not take these medications if you have a fever or bloody diarrhea, because those symptoms suggest a bacterial or parasitic infection rather than a virus, and slowing down your gut in that situation can make things worse. These medications are also not safe for infants and young children without a doctor’s guidance.
Ginger has some evidence behind it as a natural anti-nausea remedy. A randomized controlled trial published in Alimentary Pharmacology & Therapeutics found that ginger reduced vomiting episodes in children with acute gastroenteritis. Ginger tea, ginger chews, or ginger capsules are all reasonable options if you’d rather avoid medication or want something in addition to it.
Preventing Spread at Home
You remain contagious for at least 48 hours after your last episode of vomiting or diarrhea. During that window, and while you’re actively sick, a few precautions protect the people around you.
Wash your hands thoroughly with soap and water after every trip to the bathroom and before touching shared surfaces. Hand sanitizer is less effective against norovirus than actual handwashing, so soap and water is the better choice here.
If vomit or diarrhea contacts any surface, clean it with a bleach solution: 5 to 25 tablespoons of standard household bleach (5% to 8% concentration) per gallon of water. Let it sit on the surface for at least five minutes before wiping. Alternatively, use a disinfectant that’s EPA-registered as effective against norovirus. Regular household cleaners may not kill the virus.
Wash contaminated clothing and linens on the hottest setting your machine offers, and dry them completely. If someone in your household is sick, give them their own towel, and don’t share cups or utensils. Children should stay home from school or daycare until 48 hours after symptoms stop, and the same rule applies to anyone who prepares food for others.
Signs of Dehydration to Watch For
Mild dehydration shows up as increased thirst and darker or less frequent urine. You might feel lightheaded when you stand up. At this stage, stepping up your fluid intake with an ORS is usually enough.
More concerning signs in adults include very little or no urine output for eight or more hours, a dry mouth, dizziness that doesn’t pass, or a rapid heartbeat. In children, watch for dry lips and mouth, no tears when crying, sunken eyes, and skin that doesn’t spring back quickly when you gently pinch it. A child who is unusually sleepy, irritable, or refusing to drink needs prompt medical attention.
Severe dehydration, where someone has lost 10% or more of their body weight in fluid, is a medical emergency. Confusion, extreme lethargy, and very decreased skin elasticity all signal that oral fluids alone won’t be enough and intravenous rehydration is needed.