Most gastroenteritis clears up on its own within one to three days, and the single most important thing you can do is replace the fluids you’re losing. The stomach bug itself rarely needs medication. What makes people dangerously sick is the dehydration that comes with repeated vomiting and diarrhea, so treatment centers almost entirely on staying hydrated, eating when you can, and knowing when the situation has become serious enough for medical care.
Rehydration Is the Core Treatment
Every bout of vomiting or diarrhea pulls water and essential salts out of your body. Replacing both is the priority. Plain water alone isn’t ideal because it lacks the sodium and potassium your gut needs to actually absorb the fluid. The most effective approach is an oral rehydration solution (ORS), which contains a precise balance of sugar and salt that speeds water absorption through the intestinal wall.
The WHO’s standard homemade recipe is 8 level teaspoons of sugar and 1 level teaspoon of salt dissolved in 1 liter of water. This produces roughly 116 mmol/L of glucose and 86 mmol/L of sodium, concentrations that fall within the therapeutic range for rehydration. Premade solutions like Pedialyte or store-brand electrolyte drinks follow similar formulations and are convenient if you don’t want to measure.
If you’re vomiting frequently, take small sips every few minutes rather than gulping a full glass. A teaspoon or tablespoon at a time, repeated consistently, keeps fluid moving in without triggering another round of vomiting. Gradually increase the amount as your stomach settles. For adults who aren’t vomiting, aim to drink at least a cup of fluid after every loose stool.
What to Eat During Recovery
You may have heard of the BRAT diet (bananas, rice, applesauce, toast) as the go-to for a stomach bug. It’s been a staple recommendation for decades, but current clinical evidence doesn’t support it as a treatment. Sticking to only those four foods for more than a day can leave you short on protein, fat, and calories right when your body needs energy to recover.
The better approach is to return to a normal diet as soon as you can tolerate it. Start with small, bland meals and build from there. Good early choices include plain rice, crackers, boiled potatoes, chicken, soup, and bread. Avoid greasy, spicy, or heavily sweetened foods until your gut settles, but don’t restrict yourself to a handful of items. Children especially should resume their regular diet quickly, including breast milk or formula for infants, because adequate nutrition speeds intestinal recovery.
When Medication Helps (and When It Doesn’t)
Anti-diarrheal medications can reduce the frequency of loose stools, but they come with important restrictions. Loperamide (Imodine) is contraindicated if you have bloody diarrhea, high fever, or a suspected bacterial infection. It works by slowing gut motility, which can trap harmful bacteria inside rather than letting your body flush them out. It should never be given to children under 2.
Over-the-counter bismuth subsalicylate (Pepto-Bismol) can ease nausea and diarrhea in milder cases. Anti-nausea medications prescribed by a doctor may help if vomiting is severe enough to prevent any fluid intake. Antibiotics are not useful for most gastroenteritis because the vast majority of cases are caused by viruses, not bacteria. Even many bacterial cases resolve without antibiotics.
Probiotics
There’s reasonable evidence that certain probiotic strains can shorten diarrhea duration. A meta-analysis found that one well-studied strain (Lactobacillus rhamnosus GG) reduced diarrhea from acute gastroenteritis by about 24 hours and lowered the risk of symptoms dragging on past a week. Probiotics aren’t a cure, but if you want to try them, look for products that list specific strains rather than generic “probiotic blend” labels.
Zinc for Children
The WHO recommends zinc supplementation for children with diarrhea: 20 mg per day for 10 to 14 days, or 10 mg per day for infants under six months. Zinc helps restore the intestinal lining and has been shown to reduce both the severity and duration of diarrheal episodes in young children. This is standard care in many countries and is worth discussing with your pediatrician.
Signs of Dangerous Dehydration
Mild dehydration causes thirst, a dry mouth, and darker urine. That’s uncomfortable but manageable at home with consistent fluid intake. The warning signs that dehydration has become serious include:
- Very little or no urine output for 8 or more hours
- Extreme drowsiness or confusion, especially in children who become unusually sleepy or hard to wake
- No tears when crying (in infants and toddlers)
- Sunken eyes or, in infants, a sunken soft spot on the head
- Rapid heartbeat with weak pulse
- Fast, shallow breathing
Severe dehydration, defined as a fluid loss of 10% or more of body weight, is a medical emergency. At that level, the body can go into shock. Intravenous fluids are needed because the gut can no longer absorb fluid fast enough to catch up, and in some cases protective reflexes are too impaired for safe oral intake.
Children, older adults, and people with chronic illnesses reach dangerous dehydration faster than healthy adults. Infants are particularly vulnerable because their smaller body size means even modest fluid losses represent a large percentage of their total volume.
When Home Treatment Isn’t Enough
Most people recover at home without complications. But certain situations call for medical evaluation: vomiting so persistent that you can’t keep any fluids down for more than 12 to 24 hours, bloody stools, fever above 102°F (39°C), severe abdominal pain, or any of the dehydration warning signs listed above. In children, additional red flags include unusual irritability, worsening symptoms despite adequate fluid intake, and diarrhea output so high that it overwhelms oral rehydration efforts.
The CDC notes that oral rehydration tends to fail when stool output exceeds roughly 10 mL per kilogram of body weight per hour, a rate high enough that the gut simply can’t keep pace. If that’s happening, IV fluids become necessary. A very small number of infants (less than 1%) also develop carbohydrate malabsorption during acute diarrhea, where sugar-containing solutions actually worsen the diarrhea rather than help. A dramatic increase in stool output after drinking ORS is the telltale sign.
Preventing Spread at Home
Gastroenteritis, particularly norovirus, is extraordinarily contagious. A single person can shed billions of viral particles, and it takes fewer than 20 to infect someone else. If one family member is sick, protecting the rest of the household requires aggressive hygiene.
Wash your hands with soap and water, not just hand sanitizer. Alcohol-based sanitizers don’t reliably kill norovirus. Clean contaminated surfaces with a bleach solution: the CDC recommends 5 to 25 tablespoons of standard household bleach (5% to 8% concentration) per gallon of water, producing 1,000 to 5,000 parts per million of chlorine. Alternatively, use an EPA-registered disinfectant labeled as effective against norovirus. Wash soiled clothing and linens on the hottest setting and dry them completely.
The sick person should avoid preparing food for others and, if possible, use a separate bathroom. Contagiousness lasts at least 48 hours after symptoms stop, so continue precautions for two full days after the last episode of vomiting or diarrhea.