Inhaled nitrous oxide may be an ideal adjunct to the prevention of emergence reaction in adults being treated with ketamine. Nitrous oxide is a colorless gas that diffuses rapidly across the pulmonary alveoli providing analgesia and anxiolysis with minimal sedative effects, rapid induction, and emergence. Nitrous oxide is a weak sedative agent with the potential for significant analgesic effects. Noncompetitive antagonist activity at the NMDA receptor along with activation of opioid receptors contributes to its anesthetic mechanism. There are rare adverse events, most often cited as case reports of chronic or acute toxicity causing myeloneuropathies and polyneuropathies.