How long does stomach flu last?

How Long Does Stomach Flu Last?

Stomach flu—also known as viral gastroenteritis—is an infection of the intestines that causes diarrhea, vomiting, stomach cramps and sometimes fever. Despite its name, it's not caused by influenza viruses but by other highly contagious viruses, most commonly norovirus and rotavirus. Understanding how long stomach flu lasts, what to expect, and when to seek medical help can help you manage symptoms and prevent complications.

What Causes Stomach Flu?
Many different viruses can trigger gastroenteritis. The most common in adults is norovirus; in young children, rotavirus has historically been a major culprit (Parashar et al., 2006). Other viruses—adenovirus, astrovirus, sapovirus—can also cause similar illness.

Typical Symptoms
Symptoms usually appear 12–48 hours after exposure and can include:

• Watery diarrhea
• Nausea and vomiting
• Stomach cramps or pain
• Low-grade fever (occasionally higher)
• Headache, muscle aches, general weakness

Duration of Illness
How long stomach flu lasts depends on the virus involved, the individual's age and immune status, and how well complications (especially dehydration) are managed.

Norovirus (Atmar & Estes, 2006; Patel et al., 2009)

• Incubation: 12–48 hours after exposure
• Acute phase: 1–3 days of vomiting and diarrhea
• Recovery: most people feel substantially better by day 3 or 4
• Viral shedding: virus can be present in stool for up to 2 weeks after recovery, so strict hand-washing is key

Rotavirus (Parashar et al., 2006)

• Incubation: about 2 days
• Acute phase: 3–8 days of diarrhea, vomiting and fever
• Recovery: symptoms typically ease by day 5–7, though mild diarrhea may linger
• Vaccination: widespread rotavirus vaccination has dramatically reduced severe cases in children

Other Viral Causes

• Adenovirus or astrovirus: symptoms may last 5–9 days
• Sapovirus: illness tends to be milder and shorter (2–5 days)

Factors That Influence Duration
• Age and immune health
• Hydration and nutrition status
• Early management of dehydration
• Presence of other medical conditions

Managing Symptoms at Home
There's no specific antiviral treatment for most causes of stomach flu. Management focuses on hydration, rest and gradual return to normal diet.

1. Hydration

   • Sip small amounts of water, oral rehydration solutions or clear broths frequently
   • Avoid high-sugar drinks and caffeine (they can worsen diarrhea)

2. Diet

   • Follow the BRAT approach initially: Bananas, Rice, Applesauce, Toast
   • Gradually reintroduce lean proteins, cooked vegetables and low-fat dairy

3. Rest and Comfort

   • Get plenty of rest; lie still and avoid strenuous activity
   • Use a heating pad or warm compress on the abdomen to ease cramps

4. Over-the-Counter Remedies

   • Anti-diarrheal medications (e.g., loperamide) may help adults but aren't usually recommended for young children
   • Acetaminophen can relieve fever and aches; avoid NSAIDs if you're dehydrated

Preventing Spread

• Wash hands thoroughly with soap and water—especially after using the bathroom and before handling food
• Clean and disinfect contaminated surfaces with a bleach-based cleaner
• Stay home until at least 48 hours after symptoms resolve to avoid passing the virus on

When to Seek Medical Care
Most people recover fully without medical intervention. However, contact a doctor or seek immediate care if you experience:

• Signs of severe dehydration (dizziness, very dry mouth, little or no urination)
• Bloody stools or black, tarry stools
• High fever (over 102°F/39°C) lasting more than 2 days
• Repeated vomiting that prevents you from keeping liquids down
• Severe abdominal pain or persistence of symptoms beyond a week

For Peace of Mind
If your digestive symptoms persist beyond the typical stomach flu timeline or you're concerned your symptoms might indicate a chronic condition like IBS, you can check your symptoms with Ubie's free AI tool to help determine whether you should see a doctor.

Key Takeaways

• Most cases of stomach flu last 1–3 days (norovirus) or up to 7–8 days (rotavirus)
• Focus on hydration, rest and gradual diet progression
• Strict hand hygiene and surface disinfection prevent spread
• Watch for warning signs of dehydration or complications
• If symptoms are severe, persistent or you're in a high-risk group, speak to a doctor

Disclaimer
This information is for educational purposes. Always speak to a doctor about anything that could be life threatening or serious.