15663 Carbon Monoxide Poisoning
Informed by recognized medical guidance
Overview
Carbon monoxide poisoning happens when you breathe in too much carbon monoxide (CO). This is a gas that has no color, smell, or taste. It is released when fuels like gas, wood, coal, or oil do not burn fully. Once in your blood, carbon monoxide stops your red blood cells from carrying oxygen to your body. Without oxygen, your organs and tissues can be harmed.
Key facts
- You cannot see, smell, or taste carbon monoxide, which is why it is called the 'silent killer'.
- Even low levels of carbon monoxide can cause symptoms that are easily mistaken for the flu.
- A simple carbon monoxide detector in your home can save your life.
Carbon monoxide poisoning is not rare. Every year, thousands of people visit emergency departments because of carbon monoxide exposure. Many of these cases happen in the colder months when people use heaters and fireplaces.
Anyone can be affected, but babies, unborn children, older adults, and people with heart, lung, or blood conditions are more vulnerable. People who use fuel-burning appliances in poorly ventilated spaces are at the highest risk.
Symptoms
- Loss of consciousness or fainting
- Seizure
- Trouble breathing or shortness of breath
- Chest pain
- Confusion or acting strangely
- Severe drowsiness or being hard to wake
- If you suspect carbon monoxide exposure, leave the area immediately and call your local emergency number — even if you feel okay
- ⚠Mild headache
- ⚠Nausea or vomiting
- ⚠Dizziness
- ⚠Flu-like symptoms without a fever
- ⚠Symptoms that get better when you go outside but return inside
Common symptoms
- Headache
- Dizziness
- Nausea
- Vomiting
- Tiredness or weakness
- Shortness of breath
- Chest pain
- Confusion
- Fast heartbeat
- Blurred vision
Symptoms in children
- Irritability
- Drowsiness or being hard to wake
- Poor feeding
- Nausea and vomiting
- Floppy or listless feeling
- Unusual sleepiness
Symptoms in older adults
- Confusion
- Memory problems
- Flu-like symptoms without a fever
- Fainting or near-fainting
- Chest pain or worsening heart problems
- Unsteadiness and falls
Causes
Main causes
- Blocked, faulty, or poorly ventilated fuel-burning appliances, such as boilers, gas fires, wood stoves, and ovens
- Running car engines, generators, or lawn mowers in a garage or enclosed space
- Using charcoal grills or portable generators indoors, including in a house, tent, or caravan
- Blocked chimneys or flues that trap carbon monoxide inside
Risk factors
- Living in a home with an older or poorly maintained heating system
- Using a gas stove or oven to heat your home
- Power outages that lead people to use portable generators inside
- Having an attached garage and idling a car in it
- Living in a cold climate where windows are kept shut and ventilation is poor
When to see a doctor
See a doctor urgently if:
- Seek urgent medical care if you were in an enclosed space with a fuel-burning appliance and now have a headache, dizziness, nausea, or feel weak.
- If symptoms are severe, call your local emergency number right away.
Book a routine appointment if:
- If you have mild symptoms that keep coming back and you can't explain them — for example, they always happen at home and get better outdoors — see your doctor.
Diagnosis
Your doctor will ask about your symptoms, when they started, and whether you might have been exposed to carbon monoxide. They will also check your heart and lungs. A blood test is the most reliable way to measure carbon monoxide in your blood.
Tests that may be done
- A blood test to measure carbon monoxide (carboxyhemoglobin) level
- A small clip on your finger (pulse oximeter) to check oxygen levels
- An electrocardiogram (ECG) to check your heart rhythm
What to expect at your appointment
A doctor will usually take a blood sample from your arm. Results may take a few hours. While you wait, you may be given oxygen to breathe. If you came from your home, your doctor may recommend you don't go back until the source is checked by a professional.
Treatment
Treatment depends on how severe the poisoning is. The most important step is to move away from the source and breathe fresh air. In a healthcare setting, oxygen is given to help your body clear the carbon monoxide.
Self-care at home
- Get out of the area where you suspect carbon monoxide and go into fresh air immediately.
- Open doors and windows to ventilate the space if it's safe to do so.
- Do not drive yourself to the doctor — ask someone to take you or call your local emergency number.
- Speak to a gas engineer or heating technician to find and fix the source before using the appliance again.
Medical treatments
Doctors give high-flow oxygen through a face mask. For more severe cases, you might be treated in a hyperbaric oxygen chamber — a room that delivers oxygen under high pressure. This helps remove carbon monoxide from your blood faster and can reduce damage to your brain and heart. Your doctor will explain what treatment is right for you. Never be tempted to take medicines without a doctor's advice.
Living with this condition
Recovery can take time. After leaving hospital, you may feel tired, forgetful, or short of breath for a while. Plan your days with rest, and ask for help with chores if you need it. Follow any advice your doctor gives you about follow-up care, including any appointments for oxygen therapy or check-ups.
Lifestyle tips
- Install a carbon monoxide detector on every floor of your home and test it regularly.
- Get your heating system and fuel-burning appliances serviced each year by a qualified engineer.
- Never run a car engine in a garage, even if the door is open.
- Ensure all chimneys and flues are swept and checked regularly.
Diet and exercise
Eat balanced meals and drink plenty of water to help your body recover. Gentle movement, like short walks, can be helpful once your doctor says it's safe, but listen to your body. If you get short of breath or feel dizzy, stop and rest.
Mental health and emotional wellbeing
Going through carbon monoxide poisoning can be frightening, and some people feel anxious or low afterwards. It's normal to worry, especially if you were in your own home. If these feelings last, talk to your doctor. You can also find comfort in talking to family, friends, or a local support group.
Prevention
Yes, in most cases. The most important step is to install a carbon monoxide detector and keep your fuel-burning appliances well serviced. Prevention also means never using outdoor equipment like grills or generators indoors.
Complications
If left untreated
- Brain damage, including memory loss and difficulty concentrating
- Heart problems, such as an irregular heartbeat or heart muscle damage
- Long-term symptoms like fatigue, weakness, and balance problems
- In very severe cases, carbon monoxide poisoning can be fatal
Long-term outlook
With early diagnosis and treatment, most people make a full recovery. Some people may have lasting effects, but these often improve over time. The sooner you get help, the better your chance of a good outcome. There is real hope, and most people do get back to their normal life.
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
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Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 31, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.