Overview
It usually starts days after flu or chickenpox with repeated vomiting, then confusion.
Reye's syndrome causes swelling in the liver and brain.
It's linked to aspirin use during a viral illness in children.
Symptoms
Common signs:
- Repeated vomiting after a virus
- Confusion or unusual behavior
- Seizures
Less common
- Sleepiness
Look up a symptom: Fever · New confusion or not acting like themselves · Vomiting
When to get medical care
Causes
Linked to aspirin during viral illness.
Does it spread or run in families?
- It isn't contagious. You can't catch it from someone else.
Who is more likely to get it
- Children and teens
- Children and teens given aspirin during flu or chickenpox: Highest risk
Possible complications
- Seizures: From brain swelling
- Brain injury: Can be lasting
Diagnosis
This is diagnosed in the emergency room or hospital.
The exam
A physical exam.
Tests
Tests, if needed:
- Blood tests:
Treatment
Emergency care is needed. While waiting for help:
Self-care
- Call 911
Prevention
To lower your risk or catch problems early:
- Avoid aspirin and products with salicylates in children
Which doctor treats this
- Emergency doctors treat it first, in the ER.
- They may send you to a neurologist (brain and nerve doctor).
Living with it
Support groups and helplines
- Genetic and Rare Diseases Information Center (GARD): Free NIH information on rare diseases, including where to find experts and patient groups.
- National Organization for Rare Disorders (NORD): Patient groups, help finding care, and aid programs for rare diseases.
Back to school, work, or sports
- Recovery time varies. Ask your care team when you can drive, lift, work, and exercise.
Children, pregnancy, and older adults
- Children and teens: Never give aspirin unless a doctor says to.
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your prenatal provider about this condition.
- Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
- Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
- Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.
For caregivers
- Go to visits when you can and take notes.
- Keep a list of medicines, allergies, and doctors in one place.
- Learn the warning signs that need fast care.
- Learn CPR. Many hospitals and the Red Cross offer classes.
- Take breaks and ask for help. Caregivers need care too.
Outlook
Early care improves recovery.
Getting ready for your visit
Bring a list of your symptoms and medicines.
What to bring
- A list of your medicines and supplements
- Notes on when symptoms started and what makes them better or worse
Questions to ask
- What follow-up care do I need?
- How can I prevent this from happening again?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Sources
Last updated 2026-11-12.