A stomach bug typically runs its course in one to three days, and the most important thing you can do is stay hydrated while your body fights off the virus. There’s no medication that kills the virus itself, so treatment is about managing symptoms, replacing lost fluids, and knowing when things have crossed the line from uncomfortable to dangerous.
What You’re Dealing With
Most stomach bugs are caused by norovirus (the leading cause in adults) or rotavirus (more common in young children). Symptoms usually start 12 to 48 hours after exposure and include watery diarrhea, vomiting, nausea, stomach cramps, and sometimes a low fever or chills. Norovirus illness typically lasts one to three days. Rotavirus can stretch to three to seven days in infants, and adenovirus infections in toddlers can linger for five to 12 days.
The illness itself isn’t usually dangerous for healthy adults. The real threat is dehydration from all the fluid you’re losing through vomiting and diarrhea, especially for young children, older adults, and anyone with a weakened immune system.
Fluids Are the Priority
Replacing lost fluid is the single most effective thing you can do. Adults with vomiting or diarrhea should aim for about three liters of fluid per day. Children need roughly one liter per day, and babies or toddlers about half a liter. These are baseline targets; if symptoms are severe, you’ll need more.
If you’re vomiting frequently, take small sips rather than gulping a full glass. A few tablespoons every five to ten minutes is easier for your stomach to hold down than drinking a cup at once. Water works, but oral rehydration solutions (available at any pharmacy) are better because they replace the sodium and potassium you’re losing. Broth, diluted juice, and sports drinks can help too, though sports drinks have more sugar and less sodium than ideal.
For children, the math is more specific. Kids under about 22 pounds should get two to four ounces of oral rehydration solution after each episode of vomiting or diarrhea. Kids over that weight need four to eight ounces per episode. Pedialyte or similar products are better choices than juice or soda for young children because the sugar content in those drinks can actually worsen diarrhea.
What to Eat (and What to Skip)
You’ve probably heard of the BRAT diet: bananas, rice, applesauce, toast. It’s been standard advice for decades, but current medical consensus doesn’t support restricting your diet this way. Research shows that following a limited diet doesn’t help you recover faster. Once your appetite starts coming back, you can return to eating normally, even if you still have some diarrhea.
That said, listen to your body. If nothing sounds appealing, don’t force it. When you do start eating, bland foods like crackers, plain pasta, or soup tend to be easier on a sensitive stomach. Greasy, spicy, or very sweet foods may make nausea worse, so hold off on those until you feel more like yourself. The same advice applies to children: give them what they normally eat as soon as they’re ready.
Over-the-Counter Medications
Anti-diarrheal medications containing loperamide (the active ingredient in Imodium) can reduce the frequency of watery stools in adults. They’re useful if you need to get through a workday or a flight, but they won’t speed up your actual recovery. These medications should never be given to children under two, and they’re not appropriate if you have a high fever, bloody stools, or severe abdominal pain, as those symptoms may indicate a bacterial infection rather than a virus.
Bismuth subsalicylate (Pepto-Bismol) can help with nausea and an upset stomach. Avoid giving it to children or teenagers because of the risk of Reye’s syndrome, a rare but serious condition linked to salicylate products in young people.
For fever and body aches, acetaminophen is generally gentler on an already irritated stomach than ibuprofen.
When It’s More Serious
Most stomach bugs don’t need medical attention, but certain signs mean you should call a doctor or head to urgent care. For adults, the red flags are:
- Unable to keep any liquids down for 24 hours
- Vomiting or diarrhea lasting more than two days
- Blood in your vomit or stool
- Fever above 104°F (40°C)
- Severe stomach pain
- Signs of dehydration: excessive thirst, very dark urine or barely any urine, dizziness, or feeling faint
For children, the thresholds are lower. Call your pediatrician if your child has a fever of 102°F (38.9°C) or higher, bloody diarrhea, unusual tiredness or irritability, or signs of dehydration like a dry mouth, no tears when crying, or noticeably less urination than normal. For babies specifically, no wet diaper in six hours, a sunken soft spot on the head, or frequent vomiting all warrant an immediate call.
How Long You’re Contagious
This is the part most people underestimate. With norovirus, you’re most contagious while you have symptoms and for at least the first few days after you feel better. But you can continue shedding the virus for two weeks or more after your symptoms resolve. That means you can still pass it to others long after you feel fine.
Wash your hands thoroughly with soap and water after using the bathroom and before touching food. Alcohol-based hand sanitizers are less effective against norovirus than actual handwashing, so soap and water is the better choice here.
Cleaning Up After a Stomach Bug
Norovirus is remarkably tough to kill. Regular household cleaners often won’t do the job. The CDC recommends using a bleach solution: five to 25 tablespoons of standard household bleach (5% to 8% concentration) per gallon of water. Apply it to contaminated surfaces, including bathroom counters, toilet handles, and any area that came into contact with vomit or stool, and leave it on for at least five minutes before wiping.
Wash contaminated clothing and linens on the hottest water setting your machine offers, and dry them on high heat. If someone vomited on carpet or upholstery, clean the area with the bleach solution if the material can tolerate it, or use an EPA-registered disinfectant labeled as effective against norovirus. Handle soiled items carefully and wash your hands immediately afterward.
If multiple people in your household are getting sick in sequence, shared surfaces like doorknobs, light switches, and remote controls are likely culprits. Disinfect these daily until at least a few days after the last person recovers.