Carbon Monoxide Poisoning: Symptoms and Treatment

Medically Reviewed By Darragh O'Carroll, MD
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Carbon monoxide poisoning occurs when you inhale carbon monoxide, a highly toxic, colorless gas. It can cause dizziness, tiredness, shortness of breath, and even death. Sources of carbon monoxide include burning wood, gas, propane, coal, and car engines. According to the Centers for Disease Control and Prevention (CDC), over 400 people in the United States die each year from accidental carbon monoxide poisoning unrelated to fires. Additionally, over 20,000 people visit the emergency room each year for carbon monoxide poisoning. 

This article explains carbon monoxide poisoning and its symptoms, treatment, and prevention.

What is carbon monoxide?

Smoke coming from a vehicle's exhaust pipe
Hisham Ibrahim/Getty Images

Carbon monoxide is a colorless, odorless, and tasteless gas that forms when fuels partially burn. It can build up quickly and is highly poisonous in high concentrations. 

When a person inhales carbon monoxide, it enters their bloodstream and combines with hemoglobin to create carboxyhemoglobin (COHgb). Hemoglobin is the protein in your red blood cells that carries oxygen through your body. The presence of COHgb renders your red blood cells unable to transport oxygen. In turn, this can cause tissue damage and deprive the brain and heart of oxygen.

What are the causes of carbon monoxide poisoning?

Carbon monoxide comes from the fumes of burning fuels. It forms anytime you burn wood, propane, coal, and other similar fuels.

It may not be a cause for concern in open spaces. However, carbon monoxide can accumulate quickly in enclosed spaces and pose serious health risks.

Take particular caution when working with:

  • indoor fuel-burning appliances such as stoves, charcoal grills, and lanterns
  • furnaces, fireplaces, and chimneys 
  • running car engines 
  • boilers
  • petrol-powered generators 
  • naked flames
  • materials that contain methylene chloride, a substance used in many industrial processes

What are the symptoms of carbon monoxide poisoning?

Symptoms of carbon monoxide poisoning vary depending on how much of the gas you inhale. If you inhale a small amount of the gas, you may experience flu-like symptoms, including:

If you inhale high levels of carbon monoxide, you may experience more serious symptoms. These symptoms can include:

If you have symptoms of carbon monoxide poisoning, seek medical attention right away. 

How do doctors diagnose carbon monoxide poisoning?

Doctors can usually diagnose carbon monoxide poisoning by evaluating your symptoms. However, a blood test may be necessary in some cases.

Blood tests can help doctors determine the level of COHgb in your blood. Severe carbon monoxide poisoning will result in a 30% COHgb level.

Doctors may also perform an ECG to evaluate the blood supply to different parts of your body. Inadequate blood supply, known as ischemia, can indicate severe carbon monoxide poisoning.

What are the treatments for carbon monoxide poisoning?

Carbon monoxide poisoning requires urgent treatment. Treatment aims to help your body overcome the oxygen shortage.

Standard oxygen therapy involves wearing a tight-fitting mask that provides 100% concentrated oxygen. Ordinary air contains about 21% oxygen. This therapy aims to restore your body’s ability to carry oxygen to the tissues. 

Hyperbaric oxygen therapy involves entering a special chamber to breathe in pressurized, pure oxygen. This treatment removes carbon monoxide from your blood and helps your tissues heal.  

How long does it take to recover from carbon monoxide poisoning?

The time it takes to recover from carbon monoxide poisoning will depend on the level of exposure. If a person has inhaled a significant amount of the gas, it may take longer to recover. A person with significant exposure may have permanent memory or vision impairment.

What are the risk factors for carbon monoxide poisoning?

While anyone can get carbon monoxide poisoning, certain groups of people can be at increased risk. They include:

  • infants and young children
  • older adults
  • people with chronic heart disease
  • people with respiratory problems, such as asthma
  • people with anemia

People who are asleep or intoxicated can die from carbon monoxide poisoning before they notice the symptoms. This makes carbon monoxide poisoning especially dangerous for these groups.

What are some potential complications of carbon monoxide poisoning?

Exposure to significant amounts of carbon monoxide can cause severe complications, including:

  • memory loss
  • speech difficulties
  • Parkinson’s disease
  • brain damage
  • vision loss
  • harm to fetuses
  • death 

Long-term exposure to small amounts of carbon monoxide can also lead to serious complications. Seek immediate medical treatment if you suspect carbon monoxide poisoning.

How can you prevent carbon monoxide poisoning?

Because carbon monoxide is colorless, odorless, and tasteless, it is impossible to detect with the senses. However, there are ways to reduce your risk of exposure. They include: 

  • installing carbon monoxide detectors
  • opening the garage door before starting your car
  • avoiding the use of equipment that does not have the seal of a National Testing Agency
  • avoiding the use of indoor portable flameless chemical heaters 
  • using gas appliances as recommended
  • keeping your fuel-burning appliances and engines vented properly
  • letting a qualified technician install and service your boilers, cookers, heating systems, and other appliances 
  • cleaning your chimney every year
  • having a mechanic check the exhaust system of your car or truck every year  

What should you do if you suspect a carbon monoxide leak?

If you have reason to believe that there is a carbon monoxide leak, follow these steps:

  1. Switch off all appliances.
  2. Open the doors and windows to allow fresh air into the property.
  3. Leave the property immediately.
  4. Call emergency services and report the incident.
  5. Remain outside as you wait for the emergency services to arrive.
  6. Seek medical care even if you feel fine.

Other frequently asked questions

Here are a few other commonly asked questions about carbon monoxide poisoning. Dr. Darragh O’Carroll has medically reviewed the answers.

How long does it take to get carbon monoxide poisoning?

The amount of time it takes to get carbon monoxide poisoning will depend on how much carbon monoxide is in the air. It will also depend on other factors, such as your age and overall health. Extremely high levels of carbon monoxide can cause severe symptoms or even death within a few minutes.

Does carbon monoxide make you sleepy?

Exposure to carbon monoxide can make you disoriented and sleepy. If you are experiencing these symptoms, seek immediate medical treatment.

How do you check for carbon monoxide without a detector?

If you do not have a carbon monoxide detector, there are other signs you can look for to identify a leak. The air may be stale or stuffy, and there may be stains around appliances. While carbon monoxide is odorless, other gases may be present, such as exhaust.


Carbon monoxide poisoning occurs when you inhale carbon monoxide, a highly toxic, colorless gas. It can make you feel dizzy, exhausted, short of breath, and sick. Sources of carbon monoxide include burning wood, gas, propane, coal, and car engines.

Carbon monoxide poisoning requires prompt treatment. Treatment aims to remove carbon monoxide from your bloodstream and help your tissues heal. Treatment methods include standard oxygen therapy and hyperbaric oxygen therapy.

To lower your risk of carbon monoxide poisoning, install carbon monoxide detectors and keep your fuel-burning appliances properly vented. Additionally, try to open your garage before starting your vehicle, and remember to clean your chimney every year.

Seek immediate medical care if you are experiencing symptoms consistent with carbon monoxide poisoning.

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Medical Reviewer: Darragh O'Carroll, MD
Last Review Date: 2022 May 27
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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