Treatment is likely to start right away for anyone brought to an emergency room with suspected carbon monoxide poisoning. To confirm the diagnosis, the health care team might test a blood sample for carbon monoxide. This test should be done as soon as possible after removing the person from the suspected exposure environment. But the test shouldn't delay treatment.


Get into fresh air right away. Call 911 or emergency medical help if you or someone with you has symptoms of carbon monoxide poisoning. These include headache, dizziness, nausea, shortness of breath, weakness and confusion.

At the hospital, treatment may involve:

  • Breathing pure oxygen. In the emergency room, standard treatment involves breathing pure oxygen through a mask placed over the nose and mouth. This helps oxygen reach organs and tissues. People who can't breathe on their own might be put on a machine that breathes for them, called a ventilator.
  • Getting treatment in an oxygen chamber. This is called hyperbaric oxygen therapy. It involves breathing pure oxygen in a chamber for a set amount of time. The air pressure in the chamber is 2 to 3 times higher than usual. This helps replace carbon monoxide with oxygen in the blood.

    Hyperbaric oxygen therapy might be used for severe carbon monoxide poisoning. It helps protect heart and brain tissue from carbon monoxide damage. Hyperbaric oxygen therapy might also be used or pregnant women to protect unborn babies from damage from carbon monoxide poisoning.

Preparing for your appointment

If you or someone you're with has symptoms of carbon monoxide poisoning, get into fresh air immediately and call 911 or emergency medical help. Symptoms can include headache, dizziness, nausea, shortness of breath, weakness and confusion.

The health care team at the hospital will need information as soon as you arrive. On the way to the hospital, try to prepare to answer questions about:

  • Possible sources of carbon monoxide.
  • Symptoms and when they started.
  • Mental concerns, such as confusion and memory problems.
  • Loss of consciousness.
  • Other medical conditions, including pregnancy.
  • Smoking habits.
April 06, 2023
  1. What is carbon monoxide? Centers for Disease Control and Prevention. https://www.cdc.gov/co/faqs.htm. Accessed March 6, 2023.
  2. Manaker S, et al. Carbon monoxide poisoning. https://www.uptodate.com/contents/search. Accessed March 6, 2023.
  3. Carbon monoxide questions and answers. U.S. Consumer Product Safety Commission. https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center/Carbon-Monoxide-Questions-and-Ans. Accessed March 6, 2023.
  4. Chenoweth JA, et al. Carbon monoxide poisoning. Critical Care Clinics. 2021; doi:10.1016/j.ccc.2021.03.010.
  5. AskMayoExpert. Hyperbaric oxygen therapy. Mayo Clinic; 2023.
  6. Ferri FF. Carbon monoxide poisoning. In: Ferri's Clinical Advisor 2023. Elsevier; 2023. https://www.clinicalkey.com. Accessed March 6, 2023.


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Carbon monoxide poisoning