What Are the Symptoms of Oxygen Toxicity?

nausea, stomach pain, oxygen toxicity, oxygen, o2

Oxygen therapy is a lifesaver for people with COPD and other chronic (ongoing) illnesses, its benefits known to increase survival, relieve symptoms, increase exercise tolerance, improve health-related quality of life and more.[1] But what happens when you get too much oxygen? And under what circumstances could this occur? Learn the symptoms of too much oxygen and what it means to have oxygen toxicity.

History of “Pure Air”

Oxygen has existed in our atmosphere for 5 billion years, its concentration insignificant until approximately 2.5 billion years ago when the first photosynthetic organisms appeared. Joseph Priestly, the man who discovered oxygen in 1774, was one of the first to propose that adverse events may be associated with this “pure air” we now know as oxygen. But it wasn’t until 1878 that the first important contribution in the field of oxygen toxicity was made when Paul Bert, a French physiologist, demonstrated the effects of oxygen toxicity on larks. To this day, the toxic effects of oxygen on the central nervous system (CNS) are referred to as the “Bert Effect.”[2]

Who’s at Risk for Oxygen Toxicity?

In general, there are two medical settings in which oxygen toxicity might exist. The first scenario could occur anywhere the patient is exposed to very high concentrations of oxygen for short periods of time (e.g. hyperbaric oxygen therapy). The second scenario could occur where lower concentrations of oxygen are used, but for longer periods of time. These two situations could lead to what we often refer to as acute (sudden onset) and chronic (persistent, ongoing) oxygen toxicity. The acute effects often manifest as central nervous system (CNS) symptoms while chronic effects manifest in the lungs.[2]

Signs and Symptoms of Oxygen Toxicity

Signs and symptoms of oxygen toxicity are most dramatic in the central nervous system (brain and spinal cord) and the lungs, and can include the following:

    • CNS toxicity – early symptoms of CNS toxicity tend to come on suddenly and include twitching around the mouth area and small muscles of the hand. Facial pallor (ashen hue) and cogwheel breathing (peculiar, jerky inhalations) are also oxygen toxicity signs, along with headache, hiccups, shivering, tingling in the limbs, vision and hearing changes, fatigue and hyperventilation. If exposure to oxygen continues, vertigo and nausea occur, followed by behavioral changes (irritability, anxiety, confusion), clumsiness and finally convulsions. It is important to note that CNS toxicity is often accelerated by factors such as increased carbon dioxide in the blood, stress, fatigue and cold.[2]
    • Pulmonary toxicity – symptoms of pulmonary toxicity affect the lower respiratory tract including the trachea (windpipe), bronchi (air passages) and lungs. The initial sign of pulmonary oxygen toxicity manifests as a generalized pain behind the sternum (breastbone). This pain often becomes widespread, increases in intensity and is accompanied by an uncontrollable cough. Other pulmonary symptoms of too much oxygen include fever, rattling on the inhale, a tickling or burning sensation on the inhale, coughing up blood and labored breathing. Extreme cases may result in permanent scarring (fibrosis) of the lung tissue that is irreversible.[3]

Other oxygen toxicity signs include retinal edema and cataract formation with long-term exposure

Diagnosing Oxygen Toxicity Signs

Patients who are at a higher risk of developing oxygen toxicity because of long-term oxygen therapy or exposure to high concentrations of oxygen must be carefully monitored for signs and symptoms of oxygen toxicity throughout their treatment. Health care providers will check patients’ oxygen saturation regularly, as well as watching for any changes in breathing. Pulmonary function testing may take place to check for signs of respiratory distress. In addition, since some oxygen overdose symptoms are ocular in nature, eye exams may occur as well. If there are symptoms of too much oxygen present, oxygen treatment may be slowed or halted until the patient is stabilized. 

Treating Oxygen Toxicity

First and foremost, when oxygen toxicity signs appear, the exposure to the oxygen must be reduced right away. In most cases, this is enough to mitigate the oxygen overdose symptoms. Doctors are extremely careful to prescribe and administer the lowest possible concentrations of oxygen that still offer therapeutic benefits in order to avoid any symptoms of too much oxygen. Additionally, it is extremely rare for patients receiving oxygen therapy at home to show any signs or symptoms of oxygen toxicity. Still, oxygen toxicity is serious and as such, it is vital that you follow your doctor’s orders when receiving oxygen therapy and never adjust your dosage, flow rate or amount of time receiving oxygen treatment without first talking with your doctor. 

Are Oxygen Therapy Patients at Risk for Oxygen Toxicity?

The average patient using oxygen therapy according to their doctor’s instructions is not at risk for oxygen toxicity. Those at the highest risk for oxygen toxicity include deep sea divers, hospital patients, infants born prematurely who need supplemental oxygen and people who are undergoing hyperbaric oxygen therapy for carbon monoxide poisoning, cyanide poisoning and a host of other conditions.3 However, most supplemental oxygen patients are using a low enough oxygen concentration to have very little risk. Regardless, it is a good idea to be familiar with the symptoms of too much oxygen and oxygen toxicity signs. If you are at all concerned about potential oxygen overdose symptoms, call your doctor. If you or a loved one is experiencing signs and symptoms of oxygen toxicity, seek medical attention right away.

For more information about the symptoms of too much oxygen and oxygen toxicity, talk to your primary care provider.

Frequently Asked Questions: Oxygen Toxicity

Can you get too much oxygen from a machine?

It is possible to get too much oxygen from an oxygen concentrator machine. However, this is quite rare when oxygen concentrators are used as directed and prescribed. All supplemental oxygen requires a prescription from a doctor, who carefully chooses your oxygen prescription. Doctors prescribe the lowest possible concentration to their patients that will still provide therapeutic benefits in order to avoid symptoms of too much oxygen. While oxygen toxicity is still technically a risk, particularly for patients who will be using supplemental oxygen for an extended period of time, the risk is quite low when used as directed. It is vital, therefore, that patients never adjust their flow rate or the amount of time they use supplemental oxygen without first talking to their doctor. 

Can you die from too much oxygen?

Yes, but it would likely take days of excessive exposure to pure oxygen. If you have been exposed to high concentrations of oxygen already, or if you have been exposed to higher concentrations of oxygen over time, continued exposure could lead to oxygen toxicity and could be life-threatening. However, oxygen toxicity signs are usually clear enough to indicate a serious problem before it becomes life-threatening. 


[1] Stoller, James K. MD, MS, FCCP et. al. Oxygen Therapy for Patients With COPD: Current Evidence and the Long-Term Oxygen Treatment Trial. Chest. 2010 July; 138(1): 179–187. doi: 10.1378/chest.09-2555. PMCID: PMC2897694.

[2] CHAWLA, A., & LAVANIA, A. (2001). OXYGEN TOXICITY. Medical Journal, Armed Forces India, 57(2), 131–133. http://doi.org/10.1016/S0377-1237(01)80133-7

[3] Campbell, Ernest S., MD. Pulmonary Oxygen Toxicity. January 23, 2002.

Additional Resources




35 thoughts on “What Are the Symptoms of Oxygen Toxicity?”

  1. Avatar Curious says:

    Can a high altitude resident experience a degree of such toxicity if flying to a sea level destination with a sudden landing?

    1. Inogen Inogen says:

      Hi Curious, To answer your questions briefly, no, but if this is a concern of yours you should consult your primary care doctor before you fly. When you fly on commercial airlines, the cabins are pressurized to avoid changes in altitude. The people at the highest risk for oxygen toxicity are deep sea divers, hospital patients, especially infants born prematurely who need supplemental oxygen and people who are undergoing hyperbaric oxygen therapy for carbon monoxide poisoning, cyanide poisoning, etc.

  2. Avatar Plz reply says:

    I take high flow oxygen for 20 to 30 mins a couple time a day set at 10 liters would i be at risk? I take it for cluster headaches.

    1. Inogen Inogen says:

      Hi Plz Reply, Did you using your oxygen therapy device as prescribed by your doctor? If so, you should be fine. If you are concerned about oxygen toxicity, please contact your primary care provider.

  3. Avatar jamie says:

    I am on 3 liter oxygen 24/7. am I a canidate for the oxygen toxicity?

    1. Inogen Inogen says:

      Hi Jamie, As long as you are using your oxygen therapy device as prescribed by your doctor you should be fine. As we stated in the article, the average patient using oxygen therapy according to their doctor’s instructions is not at risk for oxygen toxicity.

  4. Avatar Darryl says:

    I'm on oxygen therapy 24/7 at 6 L. My 02 meter shows 99%. I checked the meter against my wife's reading which is always 95%. Do you think my meter needs to be checked, or is my reading really 99%?

    1. Inogen Inogen says:

      Hi Darryl, Normal oxygen levels range between 95-100% however if you are experiencing symptoms of low oxygen like confusion, shortness of breath, or rapid heart rate you should contact your health care provider as soon as possible. If you are concerned your home oxygen monitor is giving false results, you may want to replace it. For more information on signs of low oxygen please visit: https://www.inogen.com/blog/signs-your-loved-one-may-not-be-getting-enough-oxygen/ For more information and tips on how to use a home pulse oximetry device, please visit: https://www.inogen.com/blog/pulse-oximetry-oxygen-saturation/

  5. Avatar Joselito umipig says:

    How much inogen? Cash on delivery? Product
    Days of travel ?

    1. Inogen Inogen says:

      Hi Joselito, There are a variety of factors that go into the cost of purchase and delivery time. An Oxygen Specialist will be able to go over our different products and packages and will help you determine which oxygen concentrator is right for you. For more information, please call an Oxygen Specialist at 1-800-374-9038.

  6. Avatar jane says:

    Hi i had a breathing treatment after being exposed to wax,stripper, and paint. The nurse kept pushing me down to lie down i would sit back up couldnt breth laying down. my hand drew up in severe pain I couldnt move my body all I could do was make a grunt sound. they finally tape mask off it took awhile befor i could move. now scared to go back to hospital if i have a asthma attack caused by chemicals. was this bad?

  7. Avatar randy Moses says:

    I'm on a c-pap machine and I've been having nausea, headache, leg pain and just not feeling right.

    1. Inogen Inogen says:

      Dear Randy,
      We hope you are feeling better and this was temporary symptoms. While we are not medical professionals, we suggest you visit a doctor or urgent care clinic to determine the cause. We hope you feel better soon.

  8. Avatar Donita Brown says:

    Would too much oxygen cause pain in your shoulders and arms?

    1. Inogen Inogen says:

      Hi Donita, Too much oxygen can for some patients be just as dangerous as not enough, this is why your physician tests your oxygen levels and prescribes the proper amount (liters per minute. Please refer to your doctor and ask his/her advice on what these symptoms could be.
      Thank you!

  9. Avatar Vorbeck says:

    Any signs we can look for if too much oxygen from the machine? Eyelids turn purple? Skin turns bright red?

    1. Inogen Inogen says:

      Dear Vorbeck,
      Always consult your physician for any questions regarding flow and levels of oxygen so you keep within the guidelines prescribed to you.

  10. Avatar Rachelle Pilon says:

    I have been diagnose with COPD after 2 years of chemotherapy and my Doctor told me that I have lots of fibrosis in my lungs . Could my Chemo caused that also. Thanks

    1. Inogen Inogen says:

      Hi Rachelle, Thank you for reaching out to us. In answering your question, Yes. Here is a link to an abstract on that subject.
      https://www.ncbi.nlm.nih.gov/m/pubmed/12030733/ Take care and wishing you well.

  11. Avatar Ronnie Alery says:

    Had a 4 hr. Surgery, on oxygen during and four days in hospital stay. My Left eye has leaked water (tears) constantly from outside of eye ever since. This is problematic to me as it has never done this before my surgery. Someone told me this was due to oxygen ?

    1. Inogen Inogen says:

      Hi Ronnie,
      I have not heard this before, but then again, I am not a medical professional. I would talk to a doctor about this and hopefully they can help you resolve this quickly. Best of luck!

  12. Avatar dolores says:

    Recent oxygen therapy for person w/4th stage of progressive heart failure…breathing is a bit labored..but now on oxygen..low I believe….he is experiencing dementia symptoms…can this happen so quickly????

    1. Inogen Inogen says:

      Hi Dolores,
      I'm sorry to hear about your friend's condition. 🙁

  13. Avatar Curious says:

    Can to much oxygen kill you ?

  14. Avatar Dee says:

    I’m on oxygen. Have been for almost ten years. I’m now up to a requirement of 8 ltrs for activity. Will the inogen work for me?

    1. Inogen Inogen says:

      HI Dee,
      Unfortunately, our units will not satisfy 8 ltrs. So sorry!

  15. Avatar Jeremiah Attridge says:

    I'm usually on 4 ltrs. on a constant flow machine. I recently purchased a G 5 Inogen. What pulse level is comparable to the constant flow/?

    1. Inogen Inogen says:

      Hi Jeremiah,
      Please adjust to the setting for pulse dose per doctors orders. Thank you!

  16. Avatar Linda says:

    Been on oxygen for a while and now waking in morning feeling like a bowl of jello could this mean I am getting to much oxygen

    1. Inogen Inogen says:

      Hi Linda,
      Thank you for reaching out to us.
      We suggest you discuss this with your doctor to better understand this feeling you are experiencing.
      Take care,

  17. Avatar KR says:

    To address Jane: you should never be “forced “ by a medical professional during a procedure. You have a right to say no. I would file a complaint with hospitals patient advocacy department. Regarding fear of returning, chances of a repeat incidence is low. Try to put health and safety ahead of fears. But don’t be afraid to speak up if you have a concern. Your symptoms could be from either the toxins you were exposed to, although muscle spasms in hands and face are early warning signs. Remember normal pulse ox is 95-100%. There is no need to add oxygen if you are fully saturated unless your airway is compromised. Discuss your symptoms with a doctor and ask for a chest X-ray to make sure no actelectasis of lungs, which may clear up on their own in a few weeks. Always ask nurses what they are giving you and why. You can say no if you feel it is not right for you and ask to speak directly with doctor about your concerns.

  18. Avatar S says:

    Can you receive too much oxygen in the nose then it cause dilusion or hallucinations? In addition, can it affect co2v levels and cause a person to be sleepy? My mom was ok then suddenly she was so tired and sleepy. Keeps oxygen at a low level but day and night in a nursing home. She doesn't seem to need it.

    1. Inogen Inogen says:

      Hi S,
      Yes, you can receive too much oxygen. Too much oxygen can have the same deleterious affects as not enough oxygen. Oxygen should only be dispensed per M.D. orders.

  19. Avatar limdog says:

    I had pneumonia a few months ago and had been taking chlor oxygen to get my levels up. I guess the long term use might have been a problem because I had what appeared to be a mini stroke right after one of those doses. I could have been that my levels were improving and I wasn't weening my self off of the oxygen fast enough. Is this what you were talking about with central nervous toxicity with prolonged use of oxygen?

    1. Inogen Inogen says:

      Chloroxygen is an herbal supplement containing chlorophyll a naturally occurring substance found in green fruits and vegetables. Chlorophyll supplement may aid in red blood cell production. Red blood cells carry oxygen through your bloodstream to oxygenate tissue and organs in your body. There is no indication that chlorophyll can cause oxygen toxicity.
      Please consult your physician to discuss adding herbal supplements to prescribed medication.

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