Carbon monoxide is a poisonous gas that has no smell or taste. Breathing it incan make youunwell, and it can kill if you're exposed to high levels.

Every year in the UK, more than 200 people go to hospital with suspected carbon monoxide poisoning,which leads toaround50 deaths.

After carbon monoxide is breathed in, it enters your bloodstream and mixes with haemoglobin (the part of red blood cells that carry oxygen around your body), to form carboxyhaemoglobin.

When this happens, the blood is no longer able to carry oxygen, and this lack of oxygen causes the bodys cells andtissue to fail and die.

This topic covers the following areas:

Carbon monoxide poisoning

What causes CO to leak?

Treating CO poisoning

Complications of CO poisoning

Preventing CO poisoning

What to do if you suspect a CO leak

Being aware of the signs

At-risk groups

Content supplied by the NHS Website

Medically Reviewed by a doctor on 4 Jan 2017