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Nitrous Oxide (Laughing Gas)

The molecular structure of Nitrous oxide
  • Nitrous oxide (N2O), commonly known as laughing gas or nos, is an anaesthetic gas with pain-relieving and anti-anxiety properties. It has been used recreationally and in medicine for over 200 years. It has become widely and easily available for recreational use as it can be legally bought and sold for the purpose of making whipped cream. However, as of 2016, it is illegal to possess nitrous oxide with the intent to sell for use of its psychoactive properties.

  • Nitrous oxide is a colourless gas that has a slightly sweet smell and taste. It is usually obtained for recreational use from whipped-cream chargers. These are single use, finger-length steel canisters containing 8g of highly pressurised nitrous oxide. The gas is usually discharged into a balloon with a whipped cream dispenser, or a smaller widget called a ‘cracker’. This balloon method seems to be relatively low risk. Other sources of nitrous oxide include full-sized gas cylinders, intended for medical or industrial use. Using these is high risk outside of the intended context.

  • The exact mode of action of nitrous oxide is still unclear. However, theories have been put forward to explain its actions. There are three main ways that the body is affected by the compound. Firstly, the anti-anxiety effect is produced by the blocking of neurotransmitters by GABAA receptors. Secondly, it has been suggested that the analgesic effect is due to the stimulation of opioid receptors, resulting in the release of norepinephrine, which inhibits pain signalling throughout the body. Finally, the euphoria felt when the drug is taken is due to the release of dopamine triggered by stimulation of the brain’s reward pathway.

    The recreational effects occur at lower concentrations and may be produced by alterations in brain blood flow such as are believed responsible for the recreational effects of another gas, nitric oxide, which is produced from the sniffing of “poppers”.

  • When someone inhales nitrous oxide, the gas rapidly dissolves into the bloodstream, and reaches the brain within seconds. A rush of dizziness and euphoria is commonly reported, and people often burst into laughter. Sound distortion also occurs.

    Hallucinations are possible, from simple moving bright dots to complete detailed dreamscapes, although most users do not experience complex hallucinations. Due to the anaesthetic properties of the gas, coordination and awareness are strongly affected, and users may fall over if they are not sitting or lying down. The effects are short lasting, wearing off within two minutes. Nitrous oxide also reduces anxiety and pain.

    Additionally, when purely nitrous oxide is inhaled recreationally, the gas displaces air in the lungs, temporarily preventing much or any oxygen from reaching the blood. This may cause the heart to beat faster, and limbs to feel tingly or heavy.

  • Nitrous oxide has a long history of medical use, particularly during dental treatment and childbirth. It is used as an anaesthetic, for pain relief, and to relieve anxiety. It is also administered to patients in ambulances and used in emergency departments. In this context, the gas used is typically a 1:1 mixture of oxygen and nitrous oxide.

  • Using nitrous oxide is relatively low risk, however, it is still very important to be aware of the risks involved, and what you can do to avoid or reduce them.

    Oxygen starvation

    Inhaling nitrous oxide prevents oxygen from entering the lungs and therefore the bloodstream. This can lead to oxygen starvation which can be fatal when extreme. Some methods of inhaling nitrous oxide can increase the risk of experiencing extreme oxygen starvation. For example, inhaling directly from a canister; inhaling in an enclosed space; placing a bag over one’s head to inhale; filling a room with the gas; or using a medical mask to inhale.


    When the gas is released from its highly pressurised container, the gas and metal briefly become very cold (around -40°C). Exposure of tissue to this extreme cold can result in frostbite. Therefore, it is important to take care when opening a canister, and important to not inhale directly from the canister, as this can cause frostbite of internal tissues.

    Injury from falling

    As inhaling nitrous oxide causes dizziness, it is possible that people may lose balance and fall after inhalation, leading to injury. To prevent this, nitrous oxide should only be inhaled when sitting or lying down.

  • People with heart conditions or abnormal blood pressure may be at higher risk as the drop in oxygen levels caused by inhaling nitrous oxide raises the heart rate and can cause arrhythmias (skipped heartbeats). This could lead to cardiac arrests in susceptible people.

  • As with all drugs, mixing nitrous oxide with other substances increases the risks. Therefore, it is not advised to mix nitrous oxide with any other drugs, especially alcohol. It is possible that risks could be greater with stimulants and any other drugs that put pressure on your heart, as effects on blood pressure and heart rate could be unpredictable.

    Nitrous oxide can, allegedly, briefly multiply the effects of psychedelics like LSD (acid) and psilocybin (magic mushrooms), or bring the effects back strongly when the drug is wearing off, which could be very frightening if unexpected.

  • Due to the short-lasting effects of nitrous oxide, people are often tempted to take multiple doses over a short period of time. It is possible for people become psychologically addicted to nitrous oxide and find it difficult to resist taking it every day. Those with existing mental health conditions may be at additional risk of addictive behaviours.

  • Regular heavy use of the drug can lead to vitamin B12 deficiency. As vitamin B12 is essential for maintaining the nervous system, abuse of nitrous oxide can lead to nerve damage. Symptoms of nerve damage include tingling and numbness in fingers and toes and weakness of the arms and legs. Treatment with high doses of B12 is effective, but some damage can be irreversible. It is likely that less severe vitamin B12 deficiencies caused by nitrous oxide overuse can go undiagnosed, but cause other symptoms, such as depression, forgetfulness, and tiredness.

  • Using a balloon

    Using a balloon, with caution, is the least risky way to use nitrous oxide. Here, the gas is dispensed into a balloon from which a user inhales and exhales repeatedly until they have inhaled enough, or the gas runs out. If oxygen levels in the body drop to the degree where the user is close to losing consciousness, they will be unable to hold the balloon to their lips and will automatically begin to breathe air again. This safety mechanism minimises the risk of death by suffocation. Paying attention to any discomfort and not resisting the urge to breathe normal air will minimise the chances of harm of any kind.

    Choosing the right setting

    The risks of getting hurt if you fall or lose coordination and awareness when taking nitrous oxide can be minimised by sitting down away from hard edges and other hazards.

    Never try to fill a space with the gas

    Never attempt to fill a room, car, bag over someone’s head, or any enclosed space with nitrous oxide. This can lead to fatal oxygen starvation.

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