Also known as Dinitrogen Monoxide
Nitrous oxide, commonly known as laughing gas, is a chemical compound with the formula N2O. It is an oxide of nitrogen. At room temperature, it is a colourless, non-flammable gas, with a slightly sweet odour and taste. It is used in surgery and dentistry for its anaesthetic and analgesic effects. It is known as "laughing gas" due to the euphoric effects of inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. It is also used as an oxidizer in rocketry and in motor racing to increase the power output of engines. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen.Source: Wikipedia
Patients are most commonly prescribed nitrous oxide to treat kidney stone, inguinal hernia, knee ligament or meniscus tear, and idiopathic excessive menstruation.