The laughing gas (nitrous oxide) we use today was developed through experimentation by British chemist and inventor Humphrey Davy in 1799. He was curious to see the effect the gas would have on people and what they might do, so he began with experiments on himself.

Humphrey and his assistant Dr. Kinglake, began by heating up crystals of ammonium nitrate, collect the released gas in a green oiled-silk bag, pass this through water vapor in order to remove any impurities, and inhale it through a mouthpiece. According to records the Public Domain Review, anesthesia side-effects recorded involved giddiness, flushed cheeks, intense pleasure and the “sublime emotion connected with highly vivid ideas.” 

Eventually, the experiment conditions evolved in setting and frequency. Humphry would inhale larger amounts of the gas outside of his lab, “occupied only by an ideal existence”, and even consume it after drinking. The researcher continued to record the effects in detailed accounts but his addiction grew as well. He constructed an "air-tight breathing box" and would sit for hours at a time inhaling large amounts and almost died on several occasions. 

Early in the summer of 1799 the nitrous oxide trials began on other people. The two researchers began to give the gas to their circle of friends and had them report their experiences after. Future Poet Laureate, Robert Southey said of the experience: "O, Tom! Such a gas has Davy discovered, the gasoeus oxyd! O, Tom! I have had some; it made me laugh and tingle in every toe and finger-tip. Davy has actually invented a new pleasure for which language has no name. O, Tom! I am going for more this evening; it makes one strong and so happy, so gloriously happy! O, excellent air-bag!"

While nitrous oxcide is safe when administered by health professionals some young people have begun a trend of inhaling it for festivals, nightclubs and concerts. Ian Hamilton, a drug researcher at York University, told MailOnline: "This significant rise in deaths due to nitrous oxide use needs urgent action, we need to educate young people about the dangers of using this drug. While the drug is relatively safe, the way it is used means people are at risk of asphyxiation. These reported deaths are most likely to have been accidental rather than deliberate, that gives us an opportunity to reverse this appalling trend."