Science, Tech, Math › Science How Laughing Gas or Nitrous Oxide Works Share Flipboard Email Print JodiJacobson / Getty Images Science Chemistry Medical Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated June 30, 2019 Laughing gas or nitrous oxide is used in the dentist's office to reduce patient anxiety and relieve pain. It's also a common recreational drug. Have you ever wondered how laughing gas works? Here's a look at how laughing gas reacts in the body and whether it's safe or not. What Is Laughing Gas? Laughing gas is the common name for nitrous oxide or N2O. It is also known as nitrous, nitro, or NOS. It's a nonflammable, colorless gas that has a slightly sweet flavor and odor. In addition to its use in rockets and to boost engine performance for motor racing, laughing gas has several medical applications. It has been used in dentistry and surgery as an analgesic and anesthetic since 1844 when dentist Dr. Horace Wells used it on himself during a tooth extraction. Since that time, its use has become commonplace in medicine, plus the euphoric effect of inhaling the gas has led to use as a recreation drug. How Laughing Gas Works Although the gas has been used for a long time, the exact mechanism of its action in the body is incompletely understood, in part because the various effects depend upon different reactions. In general, nitrous oxide moderates several ligand-gated ion channels. Specifically, the mechanisms for the effects are: Anxiolytic or Anti-Anxiety EffectStudies indicate the anti-anxiety effect from inhalation of laughing gas derives from increased activity of GABAA receptors. The GABAA receptor acts as the central nervous system's principal inhibitory neurotransmitter.Painkiller or Analgesic EffectLaughing gas reduces the perception of pain by facilitating an interaction between the descending noradrenergic system and the endogenous opioid system. Nitrous oxide causes the release of endogenous opioids, but how this happens is unknown.Euphoria EffectNitrous produces euphoria by causing dopamine to be released, which stimulates the mesolimbic reward pathway in the brain. This contributes to the analgesic effect, too. Is Nitrous Oxide Safe? When you get laughing gas at the dentist's or doctor's office, it's very safe. A mask is used to first administer pure oxygen and then a mixture of oxygen and laughing gas. The effects on vision, hearing, manual dexterity and mental performance are temporary. Nitrous oxide has both neurotoxic and neuroprotective effects, but limited exposure to the chemical tends not to cause a permanent effect, one way or the other. The primary risks from laughing gas are from inhaling a compressed gas directly from its canister, which could cause severe lung damage or death. Without supplemental oxygen, inhaling nitrous oxide can cause hypoxia or oxygen deprivation effects, including lightheadedness, fainting, low blood pressure, and potentially a heart attack. These risks are comparable to those of inhaling helium gas. Prolonged or repeated exposure to laughing gas can lead to a vitamin B deficiency, reproductive problems in pregnant women, and numbness. Because very little nitrous oxide is absorbed by the body, a person inhaling laughing gas breathes out most of it. This can lead to risks to medical personnel who routinely use the gas in their practice.