What Is Gastroenteritis?

Gastroenteritis is an inflammation of your stomach and intestines. Often called the "stomach flu," it causes uncomfortable symptoms like nausea, vomiting, diarrhea, and stomach cramps. Despite its nickname, gastroenteritis is not related to influenza—the flu only affects your respiratory system.

Causes of Gastroenteritis

Viruses are the most common cause of gastroenteritis. Norovirus is the leading cause in adults, while rotavirus is more common in children. Bacteria like Salmonella, E. coli, and Campylobacter can also cause gastroenteritis, usually from contaminated food or water. Parasites and certain chemicals are less common causes.

Symptoms to Watch For

Symptoms usually appear 1 to 2 days after exposure to the virus. Common signs include watery diarrhea, stomach cramps, nausea, vomiting, and sometimes fever and body aches. Most people start feeling better within 1 to 3 days, though symptoms can last up to 10 days depending on the cause.

Is Gastroenteritis Contagious?

Yes, gastroenteritis is very contagious. The stomach flu spreads easily through close contact with infected people, sharing food or utensils, or touching contaminated surfaces. Norovirus can survive on surfaces for months. You're most contagious from when symptoms start until at least 3 days after recovery—but you can spread the virus for up to 2 weeks after feeling better.

How Long Does Stomach Flu Last?

Most people recover from stomach flu within 1 to 3 days. However, severe cases can last up to a week or longer. People with weaker immune systems, young children under 5, and adults over 65 may take longer to recover and are at higher risk for complications.

Treatment and Recovery

There's no specific cure for viral gastroenteritis. Treatment focuses on staying hydrated and resting. Drink plenty of fluids, even if you're vomiting—take small, frequent sips. Oral rehydration solutions can help replace lost electrolytes. If symptoms are severe or you become dehydrated, your doctor may prescribe anti-nausea medication or recommend IV fluids.

Prevention Tips

Wash your hands thoroughly with soap and water, especially after using the bathroom and before eating. Hand sanitizers are less effective against norovirus than handwashing. Avoid sharing food or utensils with sick people. Stay home for at least 48 hours after symptoms stop. A rotavirus vaccine is available for infants and helps prevent severe illness in children.

When to See a Doctor

Seek medical care if you have signs of dehydration (extreme thirst, dark urine, dizziness), bloody stool, fever over 104°F (40°C), or symptoms lasting more than a few days. Infants, elderly adults, and people with weakened immune systems should see a doctor early since gastroenteritis can be more serious for them.