Gastroenteritis (Stomach Flu): What It Is, Symptoms, Causes & Prevention

Gastroenteritis, commonly known as the stomach flu is an inflammation of the stomach and intestines that leads to vomiting, diarrhea, abdominal cramps, and dehydration. Although often called the “flu,” it is not caused by the influenza virus. Instead, gastroenteritis usually results from a viral, bacterial or parasitic infection.

The condition can range from mild to severe and affects people of all ages, especially young children, older adults and individuals with weak immune systems.

What Is Gastroenteritis?

Gastroenteritis is an infection that irritates the stomach and intestines, causing digestive symptoms like vomiting, nausea, and diarrhea. Acute gastroenteritis is the most common form and usually lasts 1–3 days, although severe cases may last longer.

Gastroenteritis Symptoms (Stomach Flu Symptoms)

Symptoms may begin suddenly and vary based on the cause and severity. Common gastroenteritis symptoms include:

• Watery diarrhea

• Nausea or vomiting

• Stomach pain or cramps

• Low-grade fever

• Headache

• Body aches

• Loss of appetite

• Dehydration (dry mouth, dizziness, dark urine)

Stomach Infection Symptoms in Children

Children often show additional signs such as:

• Extreme tiredness

• Irritability or fussiness

• Crying without tears

• Reduced urine output

• Sunken eyes or cheeks

• Refusal to drink or eat

Gastroenteritis in children can become serious quickly due to dehydration, so timely care is important.

Causes of Gastroenteritis (Stomach Flu)

Gastroenteritis can be caused by viruses, bacteria, or parasites. The main gastroenteritis causes include:

1. Viral Gastroenteritis

Most common cause. Viruses responsible include:

• Norovirus — affects all age groups

• Rotavirus — common in infants and children

• Adenovirus & Astrovirus — cause mild infections

Viral gastroenteritis spreads easily through contaminated food, water, hands, and surfaces.

2. Bacterial Gastroenteritis

Caused by harmful bacteria such as:

• E. coli

• Salmonella

• Shigella

• Campylobacter

Often linked to contaminated food, undercooked meat, unpasteurized milk, or poor hygiene.

3. Parasitic Infection

Less common, but parasites like Giardia lamblia or Cryptosporidium can cause stomach flu, especially in areas with poor sanitation.

4. Non-infectious Causes

Sometimes gastroenteritis may result from:

• Food intolerance (e.g., lactose intolerance)

• Medications (antibiotics, NSAIDs)

• Toxins or chemicals

How Gastroenteritis Spreads

The stomach flu spreads mainly through:

• Contaminated food or water

• Touching infected surfaces

• Close contact with an infected person

• Poor hand hygiene

• Eating improperly cooked or stored food

Gastroenteritis Diagnosis

Doctors diagnose gastroenteritis based on symptoms and medical history. Tests may include:

• Stool test (to detect bacteria/viruses)

• Blood test in severe dehydration

• Urine test (to check kidney function)

Gastroenteritis Treatment

Most cases of gastroenteritis are mild and improve with home care. Treatment focuses on reducing symptoms and preventing dehydration.

1. Rehydration

• Oral rehydration solutions (ORS)

• Plenty of fluids: water, clear soups, coconut water

• Avoid sugary drinks, caffeine, and alcohol

2. Medications

• Anti-vomiting medicines (only if prescribed)

• Antidiarrheal medications (not recommended for children unless advised)

• Antibiotics — only for certain cases of bacterial gastroenteritis

3. Diet Recommendations

• Start with soft, light foods: bananas, rice, toast, khichdi, boiled potatoes

• Avoid oily, spicy, or heavy foods

• Avoid dairy temporarily if it worsens symptoms

4. Rest

• Adequate sleep to help the immune system fight infection

Complications of Gastroenteritis

If not treated properly, gastroenteritis can lead to:

• Severe dehydration

• Electrolyte imbalance

• Kidney problems

• Seizures (in children due to dehydration)

• Shock (rare, severe cases)

Stomach Flu Prevention

Follow these steps to reduce the risk of acute gastroenteritis:

1. Maintain Proper Hygiene

• Wash hands with soap and water frequently

• Use hand sanitizer when outside

• Clean frequently touched surfaces

2. Safe Food Practices

• Drink clean, filtered water

• Avoid raw or undercooked meat

• Store food properly

• Wash fruits and vegetables thoroughly

3. Vaccination

• Rotavirus vaccine protects infants from severe viral gastroenteritis

4. Avoid Sharing Personal Items

• Towels, utensils, bottles, and cups

5. Be Careful During Travel

• Avoid roadside or unhygienic food

• Drink only bottled or purified water