Nitrous oxide has legitimate uses in healthcare, catering and industry, but wrongful inhalation can cause serious and sometimes lasting harm. Immediate risks include impaired coordination, falls, loss of consciousness, oxygen deprivation and cold injury. Repeated or heavy exposure can inactivate vitamin B12 and damage the nervous system.
Seek urgent medical help if symptoms develop after exposure. Call 999 for severe breathing difficulty, loss of consciousness, collapse, a seizure or another immediate emergency. Use NHS 111 for urgent advice when the situation is not immediately life-threatening.
What is nitrous oxide?
Nitrous oxide (N2O) is a colourless gas. Under professional supervision it is used for pain relief and sedation in medical and dental care. It also has legitimate food-industry uses, including as a propellant for whipped cream, and technical uses in manufacturing and motorsport.
Medical administration is controlled and may involve a prepared mixture with oxygen, trained staff and patient monitoring. That supervised setting is very different from wrongful inhalation outside healthcare.
What are the short-term effects and immediate risks?
Nitrous oxide can alter awareness, judgement, balance and coordination. Acute harm can include dizziness, confusion, fainting, falls and other accidental injuries. Displacing oxygen can cause hypoxia, loss of consciousness, suffocation and death.
Gas released rapidly from a pressurised cylinder becomes extremely cold. Direct contact can cause cold burns to the skin, mouth or airways. Cylinders can also cause injury if they are damaged, overheated or used with incompatible equipment.
Combining nitrous oxide with alcohol or other drugs can make the effects less predictable and increase impairment. This page does not provide inhalation methods, doses or advice intended to make misuse appear safe.
How can nitrous oxide affect vitamin B12 and the nervous system?
Prolonged or repeated exposure can inactivate vitamin B12. The Medicines and Healthcare products Regulatory Agency warns that neurological and blood-related toxicity can occur with prolonged exposure. Neurological injury can occur without anaemia and even when a standard serum B12 result is within the normal range.
Functional vitamin B12 disruption can damage the spinal cord and peripheral nerves. Possible warning signs include:
- tingling or numbness in the hands, feet or limbs;
- weakness, heaviness or reduced control of the legs;
- difficulty walking, poor balance or loss of coordination;
- muscle stiffness or unusual sensations;
- bladder or bowel changes; and
- confusion or other new neurological symptoms.
These symptoms need prompt medical assessment. Do not rely on supplements or online treatment advice to make further exposure safe. Some neurological complications can be lasting, particularly when treatment is delayed.
When should you get medical help?
Call 999 immediately for severe breathing difficulty, loss of consciousness, collapse, a seizure, severe confusion or another life-threatening emergency. Follow the call handler’s instructions.
Use NHS 111 for urgent advice if someone has new tingling, numbness, weakness, difficulty walking, balance problems or other concerning symptoms and the situation is not immediately life-threatening. A GP can also assess ongoing or recurrent symptoms and arrange specialist care where needed.
Tell the healthcare professional about the nitrous oxide exposure and the symptoms. This guide is general information and cannot diagnose a condition or replace medical advice.
Can dependence develop?
Frequent or compulsive use can develop, although the evidence around physical dependence and withdrawal is limited. Warning signs include being unable to reduce use, continuing despite harm, or allowing use to affect health, work or relationships.
Speak to a GP or a local drug and alcohol service for confidential support. FRANK provides free information and advice on 0300 123 6600 and can help people find local services.
Is nitrous oxide legal in the UK?
Nitrous oxide became a Class C controlled drug on 8 November 2023. It is unlawful to possess it where the intended use is wrongful inhalation for a psychoactive effect. Production, import, export and supply are also offences where a person knows, or is reckless as to whether, the gas is likely to be wrongfully inhaled.
Legitimate activities remain permitted, including supervised medical and dental use, catering, food production and a range of industrial or technical uses. The Home Office states that a controlled-drug licence is not required for the vast majority of legitimate non-medical users. A person may still need to demonstrate that possession is for a genuine lawful purpose.
See the current Home Office nitrous oxide guidance for the official explanation. This article provides general information and is not legal advice.
How should nitrous oxide be handled for culinary use?
For legitimate culinary use, follow the manufacturer instructions for the exact cylinder, regulator, hose, adapter and cream dispenser. Components must be compatible with one another and rated for the pressure involved.
- Keep cylinders upright, secured and away from children.
- Protect them from heat, flames, direct sunlight and physical damage.
- Inspect the cylinder, valve and equipment before use.
- Do not use damaged, leaking or incompatible components.
- Never inhale the gas or release it for wrongful inhalation.
- Do not pierce, burn, refill or modify a cylinder.
- Follow local-authority rules for disposal.
Our cream charger usage guide covers legitimate food preparation, and our disposal guide explains how to check the correct waste route.
Frequently asked questions
Can nitrous oxide cause permanent nerve damage?
Yes. Repeated or heavy exposure can inactivate vitamin B12 and cause serious neurological injury. Damage may be lasting, especially when symptoms are ignored or treatment is delayed.
Can a normal vitamin B12 blood result rule out nitrous oxide injury?
No. The MHRA states that neurological toxicity can occur even when measured B12 levels are within the normal range. A clinician may consider symptoms, exposure history and additional tests.
Is culinary nitrous oxide illegal?
No. Possession and use for a genuine culinary purpose remain lawful. Wrongful inhalation and reckless supply for wrongful inhalation are unlawful.
Do legitimate users need a controlled-drug licence?
The Home Office says licences are not required for the vast majority of legitimate users. Separate rules still apply to medicinal products and regulated professional activities.
What should I do with an empty cylinder?
Follow the manufacturer’s instructions and your council’s waste guidance. Do not place a cylinder in household recycling unless it is fully empty and the council confirms that it accepts that container type.
Official sources
- Advisory Council on the Misuse of Drugs: updated harms assessment
- MHRA: neurological and haematological toxic effects
- Home Office: nitrous oxide ban guidance
- NHS: complications of vitamin B12 deficiency
- NHS: when to call 999
- NHS: when to use NHS 111
Last materially reviewed: 1 October 2026. This page provides general health and legal information and is not a substitute for individual medical or legal advice.
