Viral diarrhea is treated primarily with fluids, rest, and time. There are no antiviral medications that target the common stomach viruses, so the goal is to replace lost fluids and electrolytes, eat when you can, and let the illness run its course. Most cases resolve within one to seven days depending on the virus, and the biggest risk is dehydration, not the infection itself.
How Long Viral Diarrhea Lasts
The two most common culprits are norovirus and rotavirus, and their timelines differ. Norovirus tends to be short and intense: 85% of people experience less than three days of vomiting and diarrhea. Rotavirus, which hits young children hardest, can stretch longer. Vomiting typically settles within 24 to 48 hours, but diarrhea can persist for two to seven days.
Knowing the typical timeline helps you gauge whether your illness is progressing normally or something else is going on. Viral diarrhea is watery and usually not bloody. If you see blood in your stool, have a high fever, or symptoms drag well past a week, a bacterial infection or parasite may be the cause instead.
Rehydration Is the Core Treatment
Replacing fluids is the single most important thing you can do. For mild cases, water, broth, and diluted juice work fine. But if you’re losing a lot of fluid through frequent watery stools or vomiting, an oral rehydration solution (ORS) is significantly more effective than water alone because it contains a precise balance of sugar and salts that helps your intestines absorb fluid faster.
The WHO’s current recommended formula uses 75 mmol/L of glucose and 75 mEq/L of sodium, a reduced-osmolarity version adopted in 2002 after the original formula occasionally caused dangerously high sodium levels in children. You can buy premade ORS packets or drinks (like Pedialyte for children or Drip Drop for adults) at most pharmacies. Sports drinks contain far more sugar and less sodium than ORS, making them a mediocre substitute.
Sip small amounts frequently rather than gulping large volumes, especially if you’re also vomiting. Taking a few tablespoons every five minutes is easier for your stomach to keep down than drinking a full glass at once.
What to Eat During Recovery
The old advice to stick to bananas, rice, applesauce, and toast (the BRAT diet) is outdated. The National Institute of Diabetes and Digestive and Kidney Diseases states plainly that research shows following a restricted diet does not help treat viral gastroenteritis. Most experts no longer recommend fasting or limiting your food choices.
Instead, go back to eating your normal diet as soon as your appetite returns, even if diarrhea hasn’t fully stopped. For children, parents should offer their usual foods right away. Your body needs calories and nutrients to recover, and bland restriction can actually slow that process. That said, greasy, very spicy, or heavily sweetened foods may feel uncomfortable on a sensitive stomach, so follow your instincts. If something doesn’t sit well, set it aside and try again later.
Over-the-Counter Medications
Loperamide (sold as Imodium) can reduce the frequency of loose stools in adults and children 12 and older. The typical approach is 4 mg after the first loose stool, then 2 mg after each subsequent one, up to 8 mg in a day. It works by slowing intestinal movement, giving your gut more time to absorb water.
There are important limits. Loperamide is contraindicated for children under 2 and is not recommended by the Infectious Diseases Society of America for managing infectious diarrhea in pediatric patients generally. It should also be avoided if you have bloody diarrhea or a high fever, both of which suggest a bacterial cause where slowing the gut could make things worse.
For vomiting that’s preventing you from keeping fluids down, a single dose of an anti-nausea medication can help. In emergency departments, children between 6 months and 12 years old are sometimes given a single dose of ondansetron (Zofran), with oral rehydration starting 15 to 30 minutes later. Adults can ask their doctor about the same approach if vomiting is severe enough to cause dehydration.
Probiotics and Zinc for Children
Certain probiotic strains may shorten the duration of diarrhea in children. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition recommends three specific strains for acute diarrhea in children: Lactobacillus rhamnosus GG, Saccharomyces boulardii (a beneficial yeast), and Lactobacillus reuteri. One review found that L. rhamnosus GG reduced diarrhea duration by roughly 20 hours. The evidence is less robust for adults, but these strains are generally safe to try.
Zinc supplementation is a WHO recommendation specifically 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 the severity and length of diarrheal episodes. This is particularly relevant in low- and middle-income settings where zinc deficiency is common, but it’s worth discussing with your pediatrician regardless.
Signs of Dangerous Dehydration
Most viral diarrhea resolves on its own, but dehydration can escalate quickly, especially in young children, older adults, and people with chronic illnesses. Watch for these warning signs:
- Very little or no urine output. Healthy hydration produces at least a modest amount of urine regularly. Dark, concentrated urine or going many hours without urinating is a red flag.
- Rapid heart rate or dizziness when standing. Fluid loss reduces blood volume, forcing your heart to beat faster. Feeling lightheaded when you stand up signals your blood pressure is dropping.
- Dry mouth, sunken eyes, or no tears in a crying child. These are classic physical signs that fluid reserves are low.
- Extreme fatigue or confusion. In severe cases, dehydration impairs organ function and mental clarity.
If someone can’t keep fluids down for more than a day, shows signs of severe dehydration, has bloody stools, or runs a fever above 102°F (39°C), they need medical attention. Children and infants reach dangerous dehydration faster than adults due to their smaller body size.
Preventing Spread to Others
Viral diarrhea is extremely contagious. Norovirus in particular spreads through tiny particles that can linger on surfaces and hands. The most important prevention measure is thorough hand washing with soap and water. Alcohol-based hand sanitizers do not work well against norovirus, so they should only be used as a supplement, never a replacement, for washing your hands.
Clean contaminated surfaces with a bleach-based disinfectant, wash soiled clothing and bedding in hot water, and avoid preparing food for others while you’re sick and for at least two days after symptoms stop. In households with multiple people, designating one bathroom for the sick person, if possible, can help contain the virus.