Carbon monoxide poisoning

toxicity due to exposure to carbon monoxide

Carbon monoxide poisoning happens from breathing in large amounts of carbon monoxide (CO).[1]

Carbon monoxide poisoning can be accidental, like if the oven's gas is left on by accident or a gas leak or caused by fires. It has often been used as a method of suicide.

Less than 200 people die per year from carbon monoxide poisoning in the UK, and that number seems to be decreasing. Around 400 people die in the US each year (published 2024).



Signs and symptoms are often "flu-like" and include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large exposures to carbon monoxide can result in loss of consciousness, arrhythmias, seizures, or death.[2]

Carbon monoxide won't show up on some tests that measure blood CO2 levels, which makes it more easily missed and dangerous.

This type of poisoning sometimes causes the nails to be affected some time after exposure. Carbon monoxide, like with arsenic, causes the blood to carrying less oxygen at any one time. This causes single white lines to appear on the nails, and can be caused by more poisonings than this, or in kidney disease. These are called Mees' lines.


  1. Schottke, David (2016). Emergency Medical Responder: Your First Response in Emergency Care. Jones & Bartlett Learning. p. 224. ISBN 978-1284107272. Archived from the original on 10 September 2017. Retrieved 2 July 2017.
  2. Guzman, JA (October 2012). "Carbon monoxide poisoning". Critical Care Clinics. 28 (4): 537–48. doi:10.1016/j.ccc.2012.07.007. PMID 22998990.