The stomach flu (viral gastroenteritis) causes miserable symptoms — vomiting, diarrhea, stomach cramps, and fever. While most cases resolve on their own within 1-3 days, some require medical treatment, especially when dehydration sets in. CityHealth Urgent Care in San Leandro can provide relief when home remedies are not enough.
Stomach Flu Symptoms
- Nausea and vomiting — often the first symptom
- Watery diarrhea — frequent, urgent bowel movements
- Stomach cramps and pain
- Low-grade fever — usually under 101°F
- Body aches and fatigue
- Loss of appetite
When to Go to Urgent Care for Stomach Flu
See urgent care if you experience any of these warning signs:
- Cannot keep fluids down for 24+ hours — risk of dehydration
- Signs of dehydration — dark urine, dizziness, dry mouth, no tears when crying (children)
- Fever above 102°F — may indicate bacterial infection
- Blood in vomit or stool
- Severe abdominal pain — especially in one location
- Symptoms lasting more than 3 days
- You are pregnant, over 65, or have a chronic condition
How Urgent Care Treats Stomach Flu
- Anti-nausea medication — ondansetron (Zofran) to stop vomiting
- IV fluids — rehydration for patients who cannot drink
- Anti-diarrheal medication — if appropriate
- Lab testing — stool culture if bacterial infection is suspected
- Electrolyte replacement — to restore balance
Stomach Flu vs. Food Poisoning
| Feature | Stomach Flu | Food Poisoning |
|---|---|---|
| Onset | 1-2 days after exposure | 2-6 hours after eating |
| Duration | 1-3 days | 1-2 days |
| Fever | Common (low-grade) | Less common |
| Contagious | Yes (highly) | No |
Both conditions are treated similarly at urgent care. Your provider can determine the cause and provide appropriate treatment. See also: food poisoning treatment.
Frequently Asked Questions
What Causes the Stomach Flu?
The stomach flu (viral gastroenteritis) is most commonly caused by:
- Norovirus — The most common cause of stomach flu in adults and older children. Extremely contagious. Spreads through contaminated food, water, or surfaces, and person-to-person contact. Outbreaks are common in schools, cruise ships, hospitals, and restaurants.
- Rotavirus — The leading cause of severe stomach flu in young children worldwide. A vaccine is available and recommended in childhood immunization schedules.
- Adenovirus and astrovirus — Less common viral causes that produce similar symptoms.
Note: The stomach flu is viral — antibiotics do not work on it. If you need antibiotics, you may have food poisoning from a bacterial source (Salmonella, E. coli, Campylobacter) or another diagnosis entirely.
Is the Stomach Flu Contagious?
Yes — the stomach flu is highly contagious. Norovirus, the most common cause, can survive on surfaces for days and spreads easily with minimal viral exposure. A person with norovirus is contagious from the moment they start feeling sick and for at least 48 hours after symptoms resolve.
To prevent spreading the stomach flu:
- Wash hands frequently with soap and water (hand sanitizer is NOT effective against norovirus)
- Stay home until at least 48 hours after vomiting and diarrhea stop
- Disinfect surfaces with bleach-based cleaners
- Do not prepare food for others while sick
- Avoid sharing cups, utensils, or towels with household members
How to Treat the Stomach Flu at Home
For mild cases, home treatment focuses on preventing dehydration:
- Hydrate slowly — Sip small amounts of clear fluids frequently. Sports drinks with electrolytes (Pedialyte for children, Gatorade, water with electrolyte packets) help replace lost minerals.
- Rest — Your immune system needs energy to fight the virus. Rest in a comfortable position.
- Eat bland food when ready — The BRAT diet (bananas, rice, applesauce, toast) is gentle on the stomach when you can tolerate food again. Avoid dairy, fatty foods, and spicy foods until fully recovered.
- Use anti-nausea medications sparingly — OTC options like bismuth subsalicylate (Pepto-Bismol) or dimenhydrinate (Dramamine) may help mild nausea. Do not give aspirin-containing products to children.
- Monitor for worsening symptoms — If you cannot keep any fluids down for 12–24 hours, it is time to seek medical care.
Signs of Dehydration: When to Seek Urgent Care
Dehydration is the most dangerous complication of the stomach flu. Watch for these warning signs:
- No urination or very dark urine for 8+ hours
- Dry or sticky mouth, excessive thirst
- No tears when crying (in children)
- Sunken eyes or fontanelle (soft spot) in infants
- Dizziness when standing up (orthostatic symptoms)
- Rapid heart rate
- Confusion or lethargy (seek ER immediately)
If you or your child shows signs of dehydration, visit CityHealth urgent care in San Leandro for IV hydration and anti-nausea treatment. Walk-ins welcome.
Should I go to urgent care for stomach flu?
Go if you cannot keep fluids down for 24+ hours, have dehydration signs, or blood in stool.
Can urgent care give IV fluids?
Yes — CityHealth provides IV fluid rehydration for dehydrated patients.
How long does the stomach flu last?
Most cases last 1-3 days. See urgent care if symptoms persist beyond 3 days.
Get Stomach Flu Relief at CityHealth
Anti-nausea meds, IV fluids, and same-day care. Open 7 days.
See our complete guide: what can urgent care treat.
How long does stomach flu last?
Stomach flu (viral gastroenteritis) typically lasts 1–3 days, though some cases can persist up to a week depending on the virus. Norovirus, the most common cause, usually resolves within 1–3 days. Rotavirus infections, more common in children, can last 3–8 days. During this time, focus on staying hydrated with clear fluids and electrolyte drinks. If symptoms persist beyond 3 days, worsen significantly, or include signs of severe dehydration, visit CityHealth San Leandro urgent care for evaluation and treatment.
Should I go to urgent care or the ER for stomach flu?
For most stomach flu cases, urgent care is the right choice — it’s faster, more affordable, and equipped to handle dehydration and nausea. Go to urgent care when you have moderate dehydration, vomiting that won’t stop, fever under 103°F, or symptoms lasting more than 3 days. CityHealth San Leandro can provide IV fluid rehydration, anti-nausea medications, and lab tests to rule out bacterial infection or food poisoning. Go to the ER instead if you notice blood in stool or vomit, severe abdominal pain, signs of shock (fainting, rapid heartbeat), or fever above 103°F that doesn’t respond to medication.
Urgent Care for Stomach Flu: What CityHealth San Leandro Provides
When stomach flu strikes, knowing where to go for urgent care can make all the difference. CityHealth San Leandro is equipped to evaluate and treat stomach flu (viral gastroenteritis) quickly and effectively. Our urgent care providers will assess your hydration status, check for signs of more serious infection, and recommend or administer appropriate treatment.
For patients with moderate to severe dehydration from stomach flu, CityHealth offers IV fluid rehydration therapy — one of the most effective treatments for restoring electrolytes and relieving symptoms like dizziness, weakness, and extreme fatigue. We also prescribe anti-nausea medications (antiemetics) such as ondansetron to help control vomiting so you can rest and recover. If bacterial infection or food poisoning is suspected rather than viral gastroenteritis, lab testing can identify the cause and guide antibiotic treatment if appropriate.
The stomach flu is one of the most common reasons patients visit urgent care, especially during fall and winter when norovirus season peaks. CityHealth San Leandro welcomes walk-in patients with stomach flu symptoms throughout the year — no appointment needed. If you’re too weak or nauseated to wait in a waiting room, call ahead and we’ll do our best to accommodate you quickly.
