Gastroenteritis doesn’t have a cure in the traditional sense, but most cases resolve on their own within one to three days. The real goal is managing symptoms, preventing dehydration, and helping your body recover faster. Viral gastroenteritis, which accounts for the vast majority of cases, won’t respond to antibiotics. What actually works is strategic rehydration, early return to normal eating, and in some cases, targeted probiotics.
Why Rehydration Is the Main Treatment
The biggest danger from gastroenteritis isn’t the infection itself. It’s the fluid and electrolyte loss from vomiting and diarrhea. Oral rehydration is the single most important thing you can do, and it works because of a specific mechanism: glucose and sodium are absorbed together through the gut wall, pulling water along with them. This is why plain water alone isn’t ideal when you’re losing fluids rapidly.
The World Health Organization’s oral rehydration solution uses a 1:1 ratio of sodium to glucose at a reduced concentration that optimizes absorption. You can buy premade oral rehydration solutions at most pharmacies. These are far more effective than sports drinks, which typically contain too much sugar and not enough sodium. If symptoms are mild and you’re keeping food down, clear broths, diluted fruit juices, and water can be enough. But if vomiting is frequent or diarrhea is severe, a proper oral rehydration solution makes a real difference, especially for children and older adults.
Take small, frequent sips rather than large gulps. If you’re vomiting, wait 15 to 20 minutes after an episode before trying again. A teaspoon every few minutes is easier to keep down than a full glass.
How Long Symptoms Typically Last
Your timeline depends on what’s causing the illness. Norovirus, the most common culprit in adults, is usually short and intense. About 85% of people experience less than three days of vomiting and diarrhea. Rotavirus, which more commonly affects young children, follows a slightly longer course: vomiting typically settles within 24 to 48 hours, but diarrhea can persist for two to seven days.
Bacterial gastroenteritis from contaminated food can last longer, sometimes five to seven days, though many bacterial cases also clear without treatment. If your symptoms haven’t improved after two days, or if you develop a high fever or notice blood in your stool, that changes the picture significantly.
What to Eat During Recovery
The old advice to stick to the BRAT diet (bananas, rice, applesauce, toast) is outdated. Research on early versus delayed refeeding shows that returning to a normal, age-appropriate diet sooner leads to better outcomes. Restricting your diet to a handful of bland foods can actually slow recovery by depriving your body of the protein, fat, and calories it needs to heal the gut lining.
That said, there’s a practical middle ground. In the first hours when nausea is worst, don’t force food. Once vomiting has settled, start eating what you can tolerate. Lean proteins, cooked vegetables, rice, bread, and soups are all reasonable. Avoid greasy, very sugary, or heavily spiced foods until you feel more stable, not because they’re dangerous, but because they’re more likely to trigger nausea. Dairy is fine for most people, though some develop temporary lactose sensitivity after a bout of gastroenteritis, so ease back into it if milk seems to worsen symptoms.
Probiotics That Shorten Illness
Not all probiotics are equal for gastroenteritis. A large meta-analysis of randomized controlled trials found that specific strains meaningfully reduce how long diarrhea lasts. Saccharomyces boulardii came out as the most effective single strain, shortening diarrhea by about 1.25 days compared to placebo. It also reduced the odds of diarrhea lasting two or more days by roughly 78%. Lactobacillus reuteri showed similar benefits, cutting diarrhea duration by about 0.84 days and also significantly reducing the risk of prolonged symptoms.
If you’re going to try a probiotic, look for products that contain one of these specific strains rather than a generic “probiotic blend.” Start taking them as early as possible once symptoms begin. The evidence is strongest for children, but the biological mechanism applies to adults as well. These are available over the counter at most pharmacies and health food stores.
Over-the-Counter Medications
Anti-diarrheal medications like loperamide can reduce the frequency of loose stools in adults, giving you some relief if you need to function. However, they work by slowing gut motility, which means the pathogen stays in your system longer. For mild viral gastroenteritis in adults, this trade-off is usually acceptable. Avoid them if you have a fever, bloody stools, or suspect a bacterial infection.
Bismuth subsalicylate (the active ingredient in Pepto-Bismol) can help with nausea and diarrhea in adults. It should not be used in children under 12, and it’s specifically dangerous for children or teenagers with flu-like illness due to the risk of Reye’s syndrome. It’s also not appropriate if you have kidney disease, bleeding disorders, stomach ulcers, or gout. If your diarrhea doesn’t improve within two days of using it, or you develop a high fever, stop taking it.
When Antibiotics Are Actually Needed
Most gastroenteritis is viral, and antibiotics do nothing for viruses. Even many bacterial cases are self-limiting. The World Health Organization recommends against routine antibiotic use for acute diarrhea because, for most pathogens, antibiotics don’t speed recovery and can cause side effects.
There are specific exceptions. Shigella infection, which typically causes bloody diarrhea with fever and cramping, always warrants antibiotic treatment because it carries significant risk of serious complications. Campylobacter gastroenteritis is treated with antibiotics mainly when it presents as dysentery (bloody stools), and treatment is most effective when started within three days of symptom onset. Non-typhoidal Salmonella should generally not be treated with antibiotics in otherwise healthy people, because treatment doesn’t improve symptoms and can actually prolong the period during which you shed bacteria in your stool.
The practical takeaway: if your stool contains blood, that’s a signal to get tested rather than to self-treat at home.
Zinc for Children With Diarrhea
For children in particular, zinc supplementation is a well-supported add-on treatment. The WHO and UNICEF recommend supplemental zinc for 10 to 14 days during and after acute diarrhea in children. It shortens the duration of diarrhea, reduces stool output, and may lower the risk of subsequent illness episodes. Recent research suggests that lower doses (5 or 10 mg daily) work just as well as the standard 20 mg dose while causing less vomiting, which matters a lot when a child is already struggling to keep fluids down.
Preventing Spread
Gastroenteritis is highly contagious, especially norovirus, which can spread through tiny amounts of stool or vomit on surfaces. Wash your hands thoroughly with soap and water after using the bathroom and before handling food. Alcohol-based hand sanitizers are less effective against norovirus than actual hand washing. Clean contaminated surfaces with a bleach-based cleaner. You remain contagious for at least 48 hours after symptoms stop, so avoid preparing food for others during that window.
For young children, rotavirus vaccination has dramatically reduced hospitalizations for severe gastroenteritis worldwide. It’s given as an oral vaccine in infancy and is part of the routine immunization schedule in most countries.