Nitrous oxide earned the nickname “laughing gas” because inhaling it triggers waves of euphoria and, in many people, uncontrollable giggling. The name traces back to the late 1790s, when the young British chemist Humphry Davy began systematically breathing the gas and documenting its effects on himself and willing friends. What Davy observed, and what countless dental patients and partygoers have experienced since, is a rapid-onset giddiness that can spill over into fits of laughter for no apparent reason. The story of how a simple molecule of two nitrogen atoms and one oxygen atom got saddled with such a playful name stretches from Georgian-era chemistry demonstrations to modern neuroscience.
Humphry Davy and the Birth of a Nickname
Joseph Priestley first isolated nitrous oxide in 1772, but Priestley was interested in gases as chemical curiosities, not as something you might deliberately breathe. It was Humphry Davy, working at the Pneumatic Institution in Bristol, who turned the gas into an experience. In the late 1790s, Davy inhaled nitrous oxide repeatedly and in escalating doses, cataloging its mental and physical effects with the rigor of a natural philosopher and the enthusiasm of a twenty-year-old. He published his findings in 1800 in a hefty volume that included reports from friends and colleagues who also tried the gas.1PubMed Central. Mini-Review: A Brief History of Nitrous Oxide (N2O) Use in Neuropsychiatry
Davy described warmth spreading through his chest, a pleasurable tingling in his limbs, a loosening of inhibition, and fits of laughter that seemed to come from nowhere. He noted that his companions often burst into laughter as well, sometimes falling over or stumbling around a room while grinning helplessly. The phrase “laughing gas” did not take long to stick. Davy’s public demonstrations became social events, and by the early 1800s, traveling showmen were staging “laughing gas frolics” where audience volunteers inhaled the gas on stage for the crowd’s entertainment. The name spread through popular culture before the gas ever entered a hospital.
What Nitrous Oxide Actually Does to Your Brain
The laughter is not random silliness. Nitrous oxide acts on several brain systems at once, and the combined effect creates a cocktail of euphoria, lowered inhibition, and altered sensory perception that many people express as laughter.
One key mechanism involves NMDA receptors, the same brain receptors targeted by ketamine. Nitrous oxide blocks these receptors, which disrupts normal glutamate signaling and produces a dissociative, floaty feeling. Because it shares this pathway with ketamine, researchers have noted that its subjective effects overlap with those of that better-known drug, including feelings of detachment, mild confusion, and a sense that things are funnier than they should be.2PubMed. Special cases: ketamine, nitrous oxide and xenon Nitrous oxide also triggers the release of the brain’s own opioid peptides in the midbrain, which activates descending pain-inhibiting pathways, particularly noradrenergic pathways, in the spinal cord.3PubMed. Neurobiology of nitrous oxide-induced antinociceptive effects In plain terms, the gas simultaneously dulls pain and floods you with a warm, pleasurable sensation. The result is the giddiness and involuntary laughter that gave the gas its name.
Personality traits may shape how strongly someone responds. One study of healthy volunteers found that people who scored higher on impulsivity tended to report greater liking of the gas during inhalation, while people with more depressive symptoms reported a stronger desire for more of it.4Oxford Academic. Rewarding Subjective Effects of the NMDAR Antagonist Nitrous Oxide (Laughing Gas) Are Moderated by Impulsivity and Depressive Symptoms in Healthy Volunteers Not everyone laughs, either. Some people get quiet and dreamy, some feel anxious, and a few feel nothing special at all. The “laughing gas” label captures the most common and memorable reaction, but it is not universal.
Beyond Giggles, the Full Sensory Experience
Laughter tends to steal the spotlight, but the subjective experience of nitrous oxide is richer and stranger than just feeling amused. A controlled experiment on 44 volunteers inhaling a sedative mixture of about 35 percent nitrous oxide confirmed a wide variety of internal sensations that had nothing to do with anything happening in the room. Participants reported phantom tastes and smells, sensations of warmth or cold, changes in how sounds and visual surroundings appeared, general heaviness, deep relaxation, and tingling throughout the body.5PubMed Central. Sensory experience induced by nitrous oxide analgesia
Some people describe the feeling as listening to music through a tunnel, or as if the edges of the room are softly vibrating. Others report time distortion, where a one-minute inhalation feels much longer or impossibly short. These effects come on within seconds and fade almost as quickly once you stop breathing the gas, which is one reason it remains popular in clinical settings. That fast on, fast off profile means a dentist can fine-tune your level of sedation in real time, something that is much harder with injected or swallowed drugs.
From Party Trick to Painkiller
For about four decades after Davy’s experiments, nitrous oxide remained a novelty. It was used for amusement, not medicine, despite Davy himself speculating in his 1800 book that the gas might be useful during surgery. The leap from entertainment to operating theater happened in Hartford, Connecticut, in December 1844, when a dentist named Horace Wells watched a volunteer at a laughing gas demonstration injure his leg without appearing to feel any pain. Wells realized the implication immediately and had a colleague extract one of his own teeth while he breathed nitrous oxide. He reportedly felt nothing.6PubMed. Horace wells’ demonstration of nitrous oxide in Boston
Wells tried to demonstrate his discovery to physicians and dentists in Boston a few weeks later, but the demonstration went badly. The patient groaned or cried out, and the audience dismissed the technique as a failure. Despite this setback, the idea that inhaled gases could eliminate surgical pain had been planted. Within a couple of years, ether and chloroform were introduced as general anesthetics, and nitrous oxide eventually found its lasting niche as a lighter, faster-acting sedative rather than a full anesthetic.7PubMed Central. Horace Wells: A Pioneer in Modern Anesthesia and Pain-Free Medical Practices Wells is now remembered as a pioneer of modern anesthesia, even though his first public showing was a humiliation.
How Dentists and Hospitals Use It Today
Nitrous oxide remains the most widely used inhalation sedative in dentistry and is common in emergency departments and outpatient surgery centers as well.8PubMed Central. Nitrous oxide as a conscious sedative in minor oral surgical procedure The concentrations used in clinical settings are modest. In dental offices, the nitrous oxide portion of the gas mixture typically does not exceed 50 percent, with the rest being pure oxygen, and local anesthesia is still used alongside it for procedures that involve actual cutting or drilling.
A systematic review pooling data from 19 clinical trials found a cumulative success rate of about 95 percent for nitrous oxide sedation in dental patients. The success rate was even higher in adults, at essentially 100 percent across the adult trials reviewed, while pediatric patients came in around 92 percent, likely because children are harder to keep cooperative regardless of sedation method.9PubMed Central. Success rate of nitrous oxide-oxygen procedural sedation in dental patients: systematic review and meta-analysis These numbers reflect the gas’s core clinical appeal: it reliably keeps patients calm during unpleasant procedures, wears off within minutes, and has a safety profile that is hard to match with other sedatives.
Outside of dentistry, nitrous oxide mixed with oxygen is used during labor in many countries, in emergency rooms for painful procedures like fracture reduction or abscess drainage, and as a bridge sedative for anxious patients before deeper anesthesia is started in the operating room. Its rapid clearance means patients can drive themselves home after a dental appointment, something that is not true of oral benzodiazepines or IV sedation.
A Possible Antidepressant
Because nitrous oxide blocks NMDA receptors in a way similar to ketamine, researchers have wondered whether it might also share ketamine’s antidepressant effects. The early evidence is genuinely intriguing. A phase 2 trial tested single one-hour inhalations of nitrous oxide at either 25 or 50 percent concentration in patients with severe treatment-resistant major depression. Both doses significantly improved depressive symptoms compared to placebo, and the lower dose worked about as well as the higher dose while causing fewer side effects.10PubMed. A phase 2 trial of inhaled nitrous oxide for treatment-resistant major depression
A systematic review and meta-analysis of the available trials confirmed that nitrous oxide produces rapid, reproducible antidepressant effects in these early-phase studies.11PubMed Central. Nitrous oxide for the treatment of depression: a systematic review and meta-analysis The open question is whether those effects can be sustained. Ketamine’s antidepressant action also fades, and patients often need repeated sessions. Whether nitrous oxide can be practically administered as a repeated treatment, and what that would look like in terms of dosing schedules and long-term safety, is still being worked out. It is worth watching but not yet something you can walk into a clinic and request for depression.
The Dark Side of Recreational Use
Nitrous oxide is easy to obtain outside of medical settings. It is sold legally in small metal canisters as a propellant for whipped cream dispensers and is used industrially to boost engine performance in motorsports.12Continuing Education in Anaesthesia Critical Care & Pain. Nitrous oxide This wide availability has made it one of the most commonly misused inhalants in the world. Users crack open whipped cream chargers, fill balloons, and inhale the gas for a few seconds of euphoria. The slang term for this practice, “doing whippets,” has become widespread enough that even case reports in medical journals use the word.
A single balloon at a party is unlikely to cause serious harm, but habitual recreational use carries real neurological risks. Nitrous oxide inactivates vitamin B12 by irreversibly oxidizing the cobalt atom at the center of the B12 molecule, which disables the enzyme (methionine synthase) that depends on it.13PubMed Central. Nitrous Oxide-Induced Vitamin B12 Deficiency and Myelopathy in Whippets Abusers: A Report of Two Cases This can happen through short-term exposure to high levels or chronic exposure to lower levels of the gas.14PubMed Central. Nitrous oxide degradation by cobalamin-dependent methionine synthase: characterization of the reactants and products in the inactivation reaction Without functional B12, the nervous system cannot properly maintain the myelin sheaths that insulate nerve fibers. The result can be myelopathy, a condition affecting the spinal cord that causes numbness, tingling, weakness in the limbs, difficulty walking, and in severe cases, paralysis.
People who already have low B12 levels, including vegans, people with absorption disorders, or heavy drinkers, are at elevated risk. Some heavy recreational users consume hundreds of canisters in a single session, and case reports of young, otherwise healthy people developing serious spinal cord damage from whippet abuse are disturbingly common in the medical literature. The damage is sometimes reversible with B12 supplementation and abstinence, but not always, especially if the spinal cord injury has progressed.
Regulation has struggled to keep pace. An analysis of Australia’s online nitrous oxide market found nearly 700 products containing the gas for sale, with few sites verifying buyer age and many offering bulk pricing that encouraged large purchases. Flavored products were common, potentially making the gas more attractive to younger users.15PubMed. Current regulations in context: Scraping Australia’s online nitrous oxide market Several countries and jurisdictions have moved to restrict sales, but the gas’s legitimate uses in food service and industry make outright bans difficult to implement.
Risks for People Who Work Around It
Recreational abusers are not the only ones at risk. Dental professionals who spend their working days in rooms where nitrous oxide is flowing face a subtler version of the same biochemical problem. A large survey of roughly 30,000 dentists and 30,000 dental assistants found that those heavily exposed to nitrous oxide reported neurological complaints, particularly numbness, tingling, and muscle weakness, at rates three to four times higher than dental professionals with no anesthetic exposure.16PubMed. Exposure to nitrous oxide and neurologic disease among dental professionals
The U.S. National Institute for Occupational Safety and Health recommends a chronic exposure limit of 25 parts per million for dental offices, but real-world measurements often exceed that threshold. A study comparing scavenged and unscavenged procedures (that is, procedures with and without a system to vacuum up exhaled nitrous oxide) found a four- to eightfold increase in ambient gas levels in the breathing zone when no scavenging system was in use.17PubMed Central. Nitrous oxide and occupational exposure: it’s time to stop laughing A more recent exposure study confirmed that nitrous oxide remains a serious concern for both short-term peak exposures and cumulative eight-hour exposures, with dentists typically receiving higher doses than their assistants.18Annals of Work Exposures and Health. Nitrous Oxide Exposure Among Dental Personnel and Comparison of Active and Passive Sampling Techniques Proper scavenging equipment, good room ventilation, and well-fitting patient masks are the standard defenses, but compliance varies widely from practice to practice.
Why Standard Brain Monitors Cannot “See” It
One quirk of nitrous oxide that matters in surgery is that it is essentially invisible to the brain-monitoring devices anesthesiologists commonly rely on. Monitors like the bispectral index (BIS) and mid-latency auditory evoked potential devices were designed to track how deeply unconscious a patient is under anesthesia. They work well for the usual inhaled and intravenous anesthetics. But nitrous oxide, like ketamine, does not lower the readings on these monitors in the expected way, even when the patient is clearly sedated.2PubMed. Special cases: ketamine, nitrous oxide and xenon This does not make it dangerous per se, but it means that when nitrous oxide is part of an anesthetic mix, the numbers on the screen can be misleading. Anesthesiologists have to rely more on clinical signs and their own judgment rather than trusting the monitor alone.
Nitrous Oxide as a Greenhouse Gas
The same molecule that makes you giggle in a dentist’s chair is also a potent greenhouse gas and a destroyer of stratospheric ozone. Nitrous oxide has roughly 296 times the global warming potential of carbon dioxide on a per-molecule basis, and it persists in the atmosphere for over a century.19Journal of Environmental Chemical Engineering. Nitrous oxide emissions, impacts and treatment technologies: Core progress and prospects of systematic, practical and applicable studies The medical and recreational uses of the gas contribute a negligible fraction of global emissions. The vast majority comes from agriculture, particularly the microbial breakdown of nitrogen-based fertilizers in soil, along with industrial processes and wastewater treatment. Still, it is a strange thought that the same substance a dentist pipes through a rubber mask to keep a child calm during a filling is also, on a planetary scale, warming the atmosphere and thinning the ozone layer.
Efforts to reduce nitrous oxide emissions focus almost entirely on agricultural and industrial sources. Precision fertilizer application, nitrification inhibitors added to soil, and improved wastewater treatment technologies are all active areas of research and regulation. The medical contribution is so small that hospitals have never been a meaningful target for emissions policy, though some health systems have started tracking anesthetic gas waste as part of broader sustainability efforts.