Gastroenteritis
Gastroenteritis — often called the 'stomach flu' — is inflammation of the stomach and intestines. Viral causes are most common, especially norovirus and rotavirus, but bacteria and parasites can also cause it.
Table of Contents
Quick Facts
- ICD-10: A09
- Most common cause: Viral (norovirus, rotavirus)
- Treatment: Fluids, rest
Symptoms
- Diarrhea (watery, sometimes bloody)
- Nausea and vomiting
- Abdominal cramps
- Fever
- Body aches
- Headache
When to Seek Urgent Care
Seek urgent care for:
- Signs of severe dehydration (very dry mouth, no urination for 8+ hours, confusion)
- Bloody diarrhea
- Severe abdominal pain
- High fever (over 39°C/102°F)
- Persistent vomiting unable to keep fluids down
- Symptoms lasting more than a few days
- Diarrhea in young infants, older adults, or immunocompromised people
Causes
Viral
- Norovirus (most common in adults)
- Rotavirus (common in young children, preventable by vaccine)
- Adenovirus, astrovirus
Bacterial
- Salmonella, Campylobacter, E. coli, Shigella
- Clostridioides difficile (usually after antibiotics)
Other
- Parasites (Giardia, Cryptosporidium)
- Food poisoning from toxins
Treatment
- Oral rehydration (sip fluids; ORS for children)
- Bland foods as tolerated (BRAT diet: bananas, rice, applesauce, toast)
- Rest
- Acetaminophen for fever and aches
- Antibiotics only for specific bacterial causes (most don't need them)
- Anti-nausea or anti-diarrheal medications used carefully and not for bloody diarrhea
Prevention
- Frequent hand washing with soap (alcohol gel is less effective against norovirus)
- Food and water safety
- Rotavirus vaccine for infants
- Clean and disinfect contaminated surfaces
When to See a Doctor
Most cases resolve in 1–3 days with rest and fluids. See a doctor for warning signs above or for diarrhea lasting more than a week.
Frequently Asked Questions
How long is the 'stomach flu' contagious?
Norovirus is contagious from the start of symptoms to at least 2 days after they stop. Bacterial gastroenteritis varies. Wash hands carefully even after feeling better.
Is it the stomach flu or food poisoning?
They overlap. Food poisoning typically refers to acute illness from contaminated food, while 'stomach flu' usually refers to viral gastroenteritis from person-to-person spread. Both are treated similarly.
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.
References
- Centers for Disease Control and Prevention. Norovirus Information.