Stomach flu (viral gastroenteritis) has no cure, so treatment is entirely about managing symptoms and preventing dehydration while the virus runs its course. Most cases resolve on their own within one to three days, though rotavirus infections can last up to eight days. The biggest risk isn’t the virus itself but the fluid and electrolyte loss from vomiting and diarrhea, which can become dangerous quickly in young children and older adults.
Hydration Is the Most Important Treatment
Replacing lost fluids is the single most effective thing you can do. Dehydration is responsible for nearly all serious complications of stomach flu, and it can develop faster than most people expect, especially when both vomiting and diarrhea are happening at the same time.
The best approach is to take small, frequent sips rather than gulping large amounts at once. If you’re vomiting, drinking too much too fast will often trigger another round. Start with a few tablespoons every five to ten minutes and gradually increase as your stomach settles. Water alone works in mild cases, but if diarrhea is heavy or prolonged, you’re losing sodium, potassium, and other electrolytes that water can’t replace.
Oral rehydration solutions (sold at most pharmacies and grocery stores) are designed specifically for this. The WHO’s recommended formula uses a 1:1 ratio of sodium to glucose, which takes advantage of a transport system in the gut that pulls water into your body most efficiently at that ratio. Commercial products use a slightly different balance (closer to 1:3 sodium to glucose) but are still effective. For children, these solutions are especially important. Avoid giving kids large amounts of plain water, as it doesn’t replace what they’re losing.
Drinks That Make Things Worse
Sugary beverages like soda, undiluted fruit juice, and sports drinks with high sugar content can actually worsen diarrhea. When a large concentration of sugar hits the intestines, it pulls water into the gut through osmosis, increasing the volume and frequency of loose stools. Caffeinated drinks like coffee and tea can also speed up the gut and contribute to fluid loss. If you want something with flavor, try diluting juice with water at a 1:1 ratio, or stick with a proper rehydration solution.
What to Eat (and What to Skip)
You may have heard of the BRAT diet (bananas, rice, applesauce, toast) as the go-to eating plan during stomach flu. Current guidelines from the National Institute of Diabetes and Digestive and Kidney Diseases actually recommend against restricted diets like BRAT. Research shows they don’t speed recovery, and they can leave you short on the calories and nutrients your body needs to heal. Once your appetite starts to return, you can go back to eating your normal diet, even if diarrhea hasn’t fully stopped.
That said, some foods are worth avoiding temporarily:
- High-fat foods like fried items, pizza, and fast food, which are harder for an irritated gut to process
- Dairy products, since the virus can temporarily damage the cells that produce lactase, the enzyme needed to digest milk sugar. Some people have trouble with dairy for a month or more after recovery.
- Highly sweetened foods and drinks, which can pull water into the intestines and worsen diarrhea
Start with whatever sounds appealing and easy on your stomach. Crackers, plain chicken, soup, and cooked vegetables are all fine choices. The key is eating when you’re ready, not forcing yourself before your appetite returns.
Over-the-Counter Medications
Anti-diarrheal medications containing loperamide (the active ingredient in Imodid) can reduce the frequency of loose stools in adults. The typical approach is two caplets after the first loose bowel movement, then one caplet after each subsequent episode, up to a maximum of eight caplets in 24 hours. These medications work by slowing down gut motility, giving your intestines more time to absorb water.
A few important limits apply. Loperamide should never be used in children under 2 years old. If diarrhea continues beyond two days of use or you develop a fever, stop taking it. The medication can also cause drowsiness and dizziness, so be cautious with driving. Taking more than the recommended amount is dangerous and has been linked to serious heart rhythm problems.
For nausea and vomiting, there’s less you can do over the counter. Some people find relief with ginger tea or ginger chews. If vomiting is so severe that you can’t keep any fluids down for more than 12 hours, that’s a sign you may need medical help.
Rest and Recovery Timeline
Most stomach flu caused by norovirus, the most common culprit in adults, peaks within the first 24 to 48 hours and resolves within one to three days. Rotavirus, which more commonly affects young children, tends to last longer, with vomiting and watery diarrhea persisting for three to eight days. Either way, the worst of it is usually the first day or two.
Your body is fighting a virus, and rest genuinely helps. Sleep when you can, and don’t rush back to work or school. You remain contagious for at least a couple of days after symptoms stop, so staying home protects the people around you too. Full energy and normal digestion may take a week or so to return, even after the acute symptoms are gone.
Preventing Spread at Home
Norovirus is extraordinarily contagious. Just a tiny number of viral particles can cause infection, and the virus survives on surfaces for days. Standard cleaning products often aren’t enough. Look for disinfectants on the EPA’s List G, which are specifically tested and registered as effective against norovirus. Check the product label for an EPA registration number and make sure the directions include use against norovirus.
If you don’t have a List G product on hand, a bleach solution works well. Mix about 5 tablespoons of household bleach per gallon of water and apply it to hard surfaces like countertops, toilet handles, and doorknobs. Let it sit for the full contact time listed on the bleach label before wiping. Wash contaminated clothing and bedding on the hottest setting your fabrics allow, and if someone has vomited, clean the area immediately while wearing gloves. Handwashing with soap and water is more effective than hand sanitizer against norovirus, so scrub for at least 20 seconds, especially before eating and after using the bathroom.
Signs of Dangerous Dehydration
Most people recover from stomach flu without complications, but dehydration can escalate quickly, particularly in infants, young children, and older adults. In adults, warning signs include excessive thirst, a dry mouth, dark yellow urine or very little urine output, and severe dizziness, weakness, or lightheadedness.
In infants and small children, the signs can be subtler. Watch for a dry mouth, crying without producing tears, unusual sleepiness or unresponsiveness, and no wet diaper for six hours or more. In babies, a sunken soft spot on the top of the head is another red flag. If you notice any of these, the child needs medical attention promptly. Severe dehydration in small children can worsen within hours.