The following information is for choking in adults. There is separate advice on how to stop a child from choking.
If the airway is only partly blocked, the person will usually be able to speak, cry, cough or breathe.
In situations like this, a person will usually be able to clear the blockage themselves.
If choking is mild:
Encourage the person to cough to try to clear the blockage.
Ask them to try to spit out the object if it's in their mouth.
Do not put your fingers in their mouth if you can't see the object, as you risk pushing it further down their mouth.
If coughing doesn't work, start back blows (see video below).
If choking is severe, the person won't be able to speak, cry, cough or breathe, and without help they'll eventually become unconscious. If coughing doesn't work start back blows.
How to do back blows (also there is a video below):
To help an adult or child over 1 year old:
Stand behind the person and slightly to one side. Support their chest with 1 hand. Lean the person forward so the object blocking their airway will come out of their mouth, rather than moving fur ther down.
Give up to 5 sharp blows between the person's shoulder blades with the heel of your hand (the heel is between the palm of your hand and your wrist).
Check if the blockage has cleared.
If not, give up to 5 abdominal thrusts.
Do not give abdominal thrusts to babies under 1 year old or to pregnant women.
To perform abdominal thrusts on a person who is severely choking and isn't in one of the above groups:
Stand behind the person who is choking.
Place your arms around their waist and bend them well forward.
Clench 1 fist and place it just above the person's belly button.
Place your other hand on top of your fist and pull sharply inwards and upwards.
Repeat this up to 5 times.
The aim is to get the obstruction out with each chest thrust, rather than necessarily doing all 5.
If the person's airway is still blocked after trying back blows and abdominal thrusts:
Call 112 / 911 / 999 (or another number for a country you're in) and ask for an ambulance.
Tell the operator that the person is choking.
Continue with the cycles of 5 back blows and 5 abdominal thrusts until help arrives.
The person choking should always be seen by a healthcare professional afterwards to check for any injuries or small pieces of the obstruction that remain.