Seek immediate advice from your GP or local accident and emergency department if you think you have carbon monoxide poisoning.

Your symptoms will often indicate whether you have carbon monoxide (CO) poisoning, but a blood test will confirm the amount of carboxyhaemoglobin in your blood. A level of 30% indicates severe exposure.

Mild carbon monoxide poisoning doesn't usually need hospital treatment, but it is still important that you seek medical advice.

Your house will also need to be checked for safety before anyone returns. Read more about what to do if you suspect a leak.

Standard oxygen therapy

Exposure to a high amount of carbon monoxide gas is treated with oxygen therapy. You will be given 100% oxygen through a tight-fitting mask (normal air contains around 21% oxygen).

Breathing in concentrated oxygen enables your body to replace carboxyhaemoglobin quicker. You will continue to receive oxygen therapy until your carboxyhaemoglobin levels decrease to less than 10%.

Hyperbaric oxygen therapy

Hyperbaric oxygen therapy (HBOT) floods the body with pure oxygen, helping it to overcome the oxygen shortage caused by carbon monoxide poisoning.

Currently, there is insufficient evidence regarding the long-term effectiveness of HBOT for treating severe cases of carbon monoxide poisoning. Therefore, standard oxygen therapy (as described above) is usually the recommended treatment option.

However, HBOT may be recommended in certain situations, such as where there has been extensive exposure to carbon monoxide, and nerve damage is suspected. The use of HBOT will be decided on a case-by-case basis.