Joseph Priestley discovered the chemical compound in 1772 and in 1799 Humphry Davy discovered, that it can be used medically.
Who Invented Laughing Gas?
No one "invented" laughing gas because it is a chemical compound known as Nitrous oxide. The first person to synthesize nitrous oxide was the English chemist Joseph Priestley in the mid-1770's. Humphry Davy, another chemist and inventor, discovered its anesthetical applications in the 1790s.