Aspirin
Tablet
Quick Summary
Aspirin stops platelets sticking together, which helps prevent blood clots in people with heart disease or after a stroke. It also relieves pain and fever.
Medical Uses
How it's taken
Take it with or after food as your doctor prescribes. Don't start daily aspirin on your own.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Indigestion
Stomach irritation.
Bleeding
Easy bruising and nosebleeds.
Asthma worsening
In some people.
Interactions
Other blood thinners
Increase bleeding risk.
NSAIDs
Such as ibuprofen; increase stomach bleeding.
Methotrexate
Aspirin can raise methotrexate levels.
Critical Warnings
Not for children under 16
Black Box Warning: Can cause Reye's syndrome, a rare serious illness.
Not in dengue
Black Box Warning: Increases bleeding risk.
Stomach bleeding
Seek help for black stools or vomiting blood.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Aspirin: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Aspirin: medicine for pain relief or preventing blood clots(opens in a new tab) · NHS