The short answer
If they can cough, let them cough. If they cannot, five sharp back blows between the shoulder blades, then five abdominal thrusts, alternating, and call 999.
- Ask "are you choking?" If they can speak, cough or breathe, encourage them to keep coughing.
- If they cannot: lean them forward and give five sharp back blows between the shoulder blades with the heel of your hand.
- Then five abdominal thrusts: stand behind, hands clenched above the navel, pull sharply inwards and upwards.
- Alternate five and five, and call 999 if it does not clear.
- If they become unconscious, start CPR.
What will ruin it
For a baby under one, use back blows and chest thrusts, never abdominal thrusts. Anyone who has had abdominal thrusts should be checked by a doctor afterwards because of the risk of internal injury.
Why it works
An effective cough moves more air than any technique you can apply from outside. Interfering with someone who is coughing effectively can turn a partial obstruction into a complete one.
This is general information, not medical advice, and it does not replace a GP, a pharmacist or NHS 111. Call 999 in an emergency. Full disclaimer.