Where the substance comes from
Nitrous oxide is a gas used in kitchens for cream whippers and in medicine as an analgesic mixed with oxygen. Its recreational spread comes from that double legality: small cartridges were freely sold, then canisters holding hundreds of doses appeared, sometimes flavoured, ordered online. Several countries have since restricted or banned sale to minors, bulk sale or misuse; the position changes fast and differs by country — that is what the country pages are for.
A little history
Nitrous oxide was obtained in 1772 by Joseph Priestley, the discoverer of oxygen. In 1799, in Bristol, the young Humphry Davy inhaled it, described the euphoria and laughter it causes — "laughing gas" — and noted, without being heeded, that it might be useful in surgery. For half a century it was above all a fairground and drawing-room attraction in England and the United States.
In 1844 the American dentist Horace Wells, after attending one of these demonstrations, used it to have a tooth pulled painlessly: one of the very first acts of anaesthesia. The gas then established itself in dentistry and obstetrics, where it is still used, mixed with oxygen, for painful procedures and childbirth. It also serves as a propellant in whipped-cream siphons — the source of the diverted cartridges.
Mass recreational use dates from the 2010s: balloons sold outside clubs, then cylinders of several hundred doses bought online. The multiplication of spinal cord damage from vitamin B12 deficiency in young adults led France to legislate on 1 June 2021 (ban on sales to minors and on diverted use), the Netherlands to ban it in January 2023 and the United Kingdom to make it a Class C drug in November 2023.
The forms it takes
The gas is transferred from cartridge or canister into a balloon and inhaled. Inhaling straight from a regulator causes cold burns to lips and airways and risks lung barotrauma.
What the user is looking for
A brief euphoria lasting tens of seconds, laughter, distorted sound. The effect is so short that it invites repetition: dozens or even hundreds of cartridges in one evening are commonly reported. It is the repetition, far more than the single dose, that does the damage.
Immediate unwanted effects
- Dizziness, falls, brief loss of consciousness.
- Asphyxia: the gas displaces oxygen. Inhaling into a bag, in a confined space or in a closed car has killed.
- Cold burns to lips, nose and lungs when inhaled directly.
- Road accidents: consciousness goes without warning.
Medium and long-term risks
Nitrous oxide inactivates vitamin B12. Without it, the sheath around nerves stops renewing. After a few weeks of intensive use come pins and needles in feet and hands, difficulty feeling the ground, an unsteady gait, sometimes genuine leg paralysis and bladder problems. Spinal cord involvement shows on MRI. Some people recover with vitamin B12 treatment and stopping the gas; others keep permanent damage. Add a risk of thrombosis, psychiatric disturbance and anaemia.
The sign that means seeing a doctor the same day
Pins and needles or numbness in feet and hands in someone using nitrous oxide. That is the first sign of nerve damage, and the stage at which treatment still works. Do not wait until walking is affected.
How to spot use
Dozens of small silver metal cartridges in a bedroom, a car or a bin, coloured canisters, balloons, crackers or regulators, cold-burned fingers and lips, an unsteady walk, complaints of pins and needles.
Why the effect is stronger in adolescents
At the same dose in a lighter body, the concentration reached is higher in an adolescent than in an adult. More importantly, the reward circuit matures well before the prefrontal cortex that is supposed to restrain it: the pull to repeat is stronger and the brake weaker, which markedly shortens the gap between first use and problem use. Use established before eighteen multiplies the risk of adult dependence whatever the substance — including legal ones such as the caffeine in energy drinks, alcohol or nicotine.
When to call an ambulance without hesitating
Loss of consciousness, seizures, severe confusion, slow or irregular breathing, blue lips, chest pain, very high temperature, uncontrollable agitation, suicidal thoughts. In those situations call the emergency services and say what was taken: treatment depends on it, and nobody is prosecuted for calling to save someone.