The best-known uses of nitrous oxide are as a medical anesthetic and analgesic. An anesthetic causes a patient to lose touch with all sensation of pain — and often lose consciousness — while an analgesic simply lessens the severity of the pain. Tylenol, for example, is an analgesic.
Worldwide, nitrous oxide is the No. 1 inhaled anesthetic in the medical profession, always administered as a 50/50 blend of nitrous oxide and pure oxygen [source: Oglesbee]. As a patient in the U.S., you're most likely to encounter nitrous oxide at the dentist's office, but in Europe, Canada and Australia it's commonly used as a pain reliever during childbirth [source: ACNM].
The chief advantages of nitrous oxide as a pain reliever are that it delivers immediate and powerful analgesic effects and can be cut off just as quickly, with patients recovering full sensation within minutes of removing a nitrous inhalation mask [source: ACNM]. Emergency medical personnel use nitrous oxide for quick pain relief during a variety of medical situations, including heart attacks, severe burns, kidney stones, fractures and dislocations [source: Oglesbee].
So how does this gas work? When nitrous oxide is inhaled, the gas enters the blood stream through the lungs and travels quickly to the brain, where it triggers the release of the body's natural opioids, endorphins and dopamine [source: ACNM]. The anesthetic effect of nitrous oxide is achieved by temporarily stabilizing neuron activity in the brain [source: Oglesbee].
In the food industry, nitrous oxide is a highly effective propellant for dispensing fatty liquids like oil and heavy cream. To dispense whipped cream, nitrous gas is compressed into a liquid and mixed with heavy cream inside sealed, pressurized canisters. Because the liquid nitrous oxide displaces all oxygen in the can, an unopened canister of whipped cream will never go rancid. Nitrous oxide is highly soluble in fat, and when pressure inside the canister is released, the liquid nitrous instantly turns to gas, expanding the volume of the cream four-fold [source: Weingarten].
Another popular use of nitrous oxide is as a fuel additive in car racing. Read the full HSW article for all of the details on how an injection of nitrous oxide improves engine performance, but here's the gist: In an internal combustion engine, oxygen is critical for igniting the fuel injected into the engine. When nitrous oxide is heated to 570 degrees F (~300 C) — racing engines run hot — it splits into nitrogen and oxygen. Adding compressed nitrous oxide to an engine significantly raises oxygen levels, which translates to more fuel being burned and more horsepower [source: Hot Rod Network].
The final popular use of nitrous oxide is as a recreational drug. More on the "buzz" and adverse side effects of nitrous oxide abuse on the next page.