Nitrous oxide

Nitrous oxide is a gas that induces a state of exhilaration and anesthesia when inhaled, with effects including laughter and pain suppression. It was initially a novelty but found practical use in dentistry as an anesthetic.
 Humphry Davy England 1800 Nitrous oxide

Nitrous oxide is a gas that induces a state of exhilaration and anesthesia when inhaled, with effects including laughter and pain suppression. It was initially a novelty but found practical use in dentistry as an anesthetic.