How Long Does the Stomach Flu Last?

Quick Answer

The stomach flu (viral gastroenteritis) lasts 1–3 days in most healthy adults. Symptoms — vomiting, diarrhea, nausea, and stomach cramps — usually peak within the first 24 hours and gradually improve. Children and older adults may take 4–6 days to fully recover.

Duration by Virus Type

Virus	Onset	Duration	Most Affected
Norovirus	12–48 hrs	1–3 days	All ages
Rotavirus	1–3 days	3–8 days	Children under 5
Adenovirus	3–10 days	5–12 days	Children
Astrovirus	1–4 days	2–4 days	Young children, elderly

Norovirus is the most common cause of stomach flu in adults. Rotavirus is the most common cause in young children (though vaccination has significantly reduced cases).

Symptom Timeline

• Hours 0–12: Nausea, loss of appetite, general malaise
• Hours 12–24: Vomiting and/or diarrhea begin, stomach cramps, possible low-grade fever
• Hours 24–48: Symptoms peak — frequent vomiting and diarrhea, body aches, fatigue
• Day 2–3: Vomiting stops, diarrhea begins to ease
• Day 3–5: Appetite slowly returns, energy improves
• Day 5–7: Full recovery (some may have lingering mild digestive sensitivity)

Stomach Flu vs. Food Poisoning

Feature	Stomach Flu	Food Poisoning
Cause	Virus (norovirus, rotavirus)	Bacteria, toxins
Onset	12–48 hours	30 min–6 hours (usually faster)
Duration	1–3 days	1–2 days (bacterial: up to 7)
Fever	Low-grade, common	Variable
Vomiting	Very common	Common
Spread	Highly contagious person-to-person	Not contagious

Contagious Period

• Contagious from onset of symptoms through 48 hours after symptoms resolve
• Norovirus can shed in stool for 2+ weeks after recovery
• Extremely contagious — as few as 18 virus particles can cause infection
• Spread through contaminated food/water, surfaces, and direct contact

How to Recover

• Hydrate, hydrate, hydrate — the biggest risk from stomach flu is dehydration. Drink water, clear broth, electrolyte solutions (Pedialyte, Gatorade diluted with water), or suck on ice chips
• Don't force food — wait until vomiting stops to eat. Start with bland foods (crackers, toast, rice, bananas)
• Rest — sleep as much as your body wants
• Avoid dairy, caffeine, alcohol, and spicy/fatty foods until fully recovered
• OTC anti-diarrheal medications (loperamide) can help adults but are not recommended for children
• Anti-nausea medication (ondansetron) may be prescribed for severe vomiting

Signs of Dehydration (Seek Care)

• Dark yellow or amber urine
• Infrequent urination (less than 3x in 24 hours)
• Dry mouth and extreme thirst
• Dizziness when standing
• Sunken eyes
• Crying without tears (in children)
• Rapid heartbeat

When to See a Doctor

• Can't keep fluids down for 24+ hours
• Vomiting blood or bloody diarrhea
• Fever above 104°F (40°C)
• Signs of severe dehydration
• Symptoms last more than 3 days
• Infants, elderly, or immunocompromised individuals

Prevention

• Wash hands thoroughly with soap (hand sanitizer is less effective against norovirus)
• Disinfect surfaces with bleach-based cleaners
• Don't prepare food for others while sick and for 48 hours after recovery
• Wash contaminated laundry on the hottest setting
• Vaccinate children against rotavirus